But let's be honest - the signings we really remember are those which go horribly wrong. For every Cristiano Ronaldo there's a Juan Sebastian Veron, for every Didier Drogba there's an Andriy Shevchenko, and for every Fernando Torres there's a...erm...Fernando Torres.
So remind yourself of these 30 transfers (since 2000) which the men in question would rather forget.
Fees given in pound sterling for transfers to/from England and China only.
30. Paco Alcácer (Valencia to Barcelona)
Fee/Transfer Window: €30m (Summer 2016)
Alcácer joined Borussia Dortmund on loan at the start of this season and continued to be used mainly as a substitute, albeit with much greater success - ten of his twelve Bundesliga goals came after starting on the bench. Dortmund exercised their right to buy him for €23m in November, so at least Barcelona got most of their money back.
29. Aly Cissokho (Porto to Lyon)
Fee/Transfer Window: €15m (Summer 2009)
It's hard to know what's more surprising: that Lyon once paid €15m for Aly Cissokho, or that they weren't the only club willing to do so. AC Milan had agreed to sign the Frenchman from Porto before he failed a medical, with doctors discovering potential spinal problems. Bullet dodged.
Cissokho was a defensive liability during three seasons at Lyon, and Valencia bought him in 2012 for a third of his original fee. The following season he was loaned to Liverpool, where he developed something like a cult status for being so bad. He found his level at Aston Villa, but left after their relegation in 2017.
28. Fernando Redondo (Real Madrid to Milan)
Fee/Transfer Window: £11m (Summer 2000)
Sir Alex Ferguson once complained that Fernando Redondo had magnets in his boots after a particularly untouchable performance for Real Madrid against Manchester United in 2000. Redondo was on his way to winning the Champions League for a second time, but was surprisingly allowed to join AC Milan at the end of the season.
Unfortunately, injury meant that Redondo couldn't make his Serie A debut for two and a half years, by which time he was 33 and past his best. He won the Champions League again in 2003, but played no part in the final, and a year later he retired from football after another knee injury.
27. Nicklas Bendtner (Arsenal to Juventus)
Fee/Transfer Window: Loan (Summer 2012)
Most people were surprised when Juventus signed Nicklas Bendtner on loan from Arsenal in 2012, but the man himself probably thought it was about time that someone acknowledged his greatness. Even he must have been daunted by the task of replacing Alessandro Del Piero though.
Predictably, the overconfident Dane never scored for Juventus, although it wasn't entirely his fault. He suffered a thigh injury in December and had to undergo surgery, meaning that he didn't play again until the final match of the season...when he got injured again. Juventus opted not to extend his loan.
26. Adrian Mutu (Parma to Chelsea)
Fee/Transfer Window: £15.8m (Summer 2003)
With just six goals in 27 Premier League appearances for Chelsea, Adrian Mutu never delivered on the potential he had shown in Serie A with Verona and Parma. But let's be honest, Mutu isn't on this list because he was a bad footballer. He's here because he tested positive so drugs while at Stamford Bridge.
In September 2004, Mutu was banned from football for seven months after testing positive for cocaine. Chelsea sought compensation for a breach of contract and a long-winded legal battle ensued. As of October 2018, Mutu is still appealing the ruling, and he still owes Chelsea over £15m.
25. Yoann Gourcuff (Bordeaux to Lyon)
Fee/Transfer Window: €22m (Summer 2010)
If you can't beat them, buy them - Lyon signed Gourcuff for €22m in 2010. In quotes recently echoed by Jamie Vardy, Gourcuff said that he struggled to adapt to the style of manager Claude Puel, and it showed, with just three goals in his debut season. Gourcuff missed over 90 games due to injury in his five years at Lyon, and he now plays for Dijon.
24. Geoffrey Kondogbia (Monaco to Inter)
Fee/Transfer Window: €31m (Summer 2015)
It wasn't completely Kondogbia's fault though. Inter went through four managers in his two seasons, and Kondogbia had a particularly fractious relationship with Frank de Boer. He admitted during his loan at Valencia that he would happily pay his own buyout clause, but Los Che were happy to oblige, making his move permanent for €25m.
23. Ciro Immobile (Torino to Borussia Dortmund)
Fee/Transfer Window: €18m (Summer 2014)
When Borussia Dortmund lost Robert Lewandowski to their biggest rivals Bayern Munich in 2014, they needed to find a player who could replace the Polish striker's prolific goal rate. They opted for Ciro Immobile, who had scored 22 goals in Serie A for Torino the previous season.
22. Jesé Rodriguez (Real Madrid to Paris Saint-Germain)
Fee/Transfer Window: €25m (Summer 2016)
Neither that move nor his subsequent stay in the Potteries went well for Jesé and he now finds himself an outcast at PSG, unable to break into Thomas Tuchel's team. Las Palmas' complaints of a poor attitude and high salary demands have made Jesé damaged goods, and at the age of 25 his career is in desperate need of defibrillation.
21. Zlatan Ibrahimovic (Milan to Barcelona)
Fee/Transfer Window: €46m plus Samuel Eto'o (Summer 2009)
Ibrahimovic's ego demands that he is top dog wherever he plays, but that was not the case at Barcelona. Forced to play in the shadow of Lionel Messi, Ibrahimovic grew frustrated with Pep Guardiola and lashed out at him after Barcelona's Champions League defeat to Inter. He was sent back to Italy at the end of the season.
20. Diego (Werder Bremen to Juventus)
Fee/Transfer Window: €24.5m (Summer 2009)
The 2009/10 season was one to forget for Juventus. They finished seventh in Serie A, failed to make it out of the Champions League group stages, and were knocked out of the Europa League by Fulham. Fans needed a scapegoat, and they laid the blame at the door of Diego, a €24.5m signing from Werder Bremen.
Diego had dazzled in Germany with 54 goals in three seasons for Bremen, but the lack of support he received from midfielders Christian Poulsen and Felipe Melo (who also appear on this list) at Juventus meant that opposition defences could easily deal with him. After one season in which he only showed flashes of brilliance, he returned to Germany.
Fee/Transfer Window: Loan (January 2009)
Or perhaps it was just a terrible signing. Faubert missed training when he thought he had a day off, fell asleep on the bench during a match against Villarreal, and made just two appearances before returning to Upton Park. This sits somewhere between Ali Dia and Bebe on the list of strangest transfers ever made.
18. Dmytro Chygrynskiy (Shakhtar Donetsk to Barcelona)
Fee/Transfer Window: €25m (Summer 2009)
Chygrynskiy played just 14 matches in all competitions for Barcelona, winning an average of one trophy every seven games, before returning to Shakhtar Donetsk at the end of the season. His name remains a footnote in an illustrious period of Barcelona's history.
17. Kaka (Milan to Real Madrid)
Fee/Transfer Window: €68.5m (Summer 2009)
But despite becoming the world's most expensive footballer when he joined Real Madrid in 2009, it soon became evident that Kaka's best years were behind him. Injuries marred his first two years at the Bernabeu, during which time Mesut Ozil took his place in the team. Kaka was sold back to Milan in 2013 for a £45.5m loss - still officially the biggest of all time.
16. Jô (CSKA Moscow to Manchester City)
Fee/Transfer Window: £19m (Summer 2008)
Jô's Manchester City career was doomed from the start. One month after arriving at the club, they were taken over by the Abu Dhabi United Group, who made Robinho - a better Brazilian striker - their first marquee signing. Jô was a relic of the old Manchester City, while Robinho was the symbol of the new one.
15. Ricardo Quaresma (Porto to Inter)
Fee/Transfer Window: €18.6m (Summer 2008)
But Quaresma's ability and attitude both came under the microscope, with Inter boss Jose Mourinho questioning his team ethic. He was 'awarded' the Bidone d'oro (Golden Bin) award for worst Serie A player at the end of his debut season, and joined Besiktas after two unhappy years.
14. Roberto Soldado (Valencia to Tottenham)
Fee/Transfer Window: £26m (Summer 2013)
The Spaniard didn't score from open play until October and managed just six goals all season. After two seasons with a painfully poor strike rate of seven goals in 52 Premier League appearances, Soldado returned to Spain with his confidence shattered, and never recaptured the form which had won him a move to England in the first place.
13. Christian Poulsen (Sevilla to Juventus) & Felipe Melo (Fiorentina to Juventus)
Fee/Transfer Window: Poulsen €9.75m (Summer 2008) Melo €25m (Summer 2009)
With the midfield completely lacking any steel, Juventus meekly surrendered to 15 Serie A defeats that season, equalling a club record for most losses in a single campaign. Poulsen left in 2010 for Liverpool, where he is equally reviled, and Melo joined Galatasaray a year later.
12. Afonso Alves (Heerenveen to Middlesbrough)
Fee/Transfer Window: £12.7m (January 2008)
Afonso Alves changed the way we think about Eredivisie strikers, and not in a good way. A track record of 45 goals in 39 league appearances for Heerenveen made him sound like the next Pele, and Middlesbrough seemed to have secured a coup by bringing him to the Riverside for a club record fee.
But Alves scored just six goals in his debut season, half of which were against a Manchester City team that had given up, and the following season was even worse, with just four Premier League goals. Unsurprisingly, having splashed most of their budget on Alves, Middlesbrough were relegated, and he disappeared to the Middle East.
11. Radamel Falcao (Monaco to Manchester United & Chelsea)
Fee/Transfer Window: Loan (Summer 2014 & Summer 2015)
Radamel Falcao was considered one of the best strikers in world football when he scored over 30 goals for four consecutive seasons between 2009 and 2013, but it was after a disappointing first year at Monaco that he decided to try and revitalise his career in the Premier League with Manchester United.
Falcao struggled to adapt and managed just four goals before returning to Monaco at the end of the season. Chelsea took up the challenge and brought him to Stamford Bridge on loan the following season, but that stint ended after ten appearances and a groin injury. He's back among the goals now, but those spells in England are best forgotten.
10. Christian Benteke (Aston Villa to Liverpool)
Fee/Transfer Window: £32.5m (Summer 2015)
Benteke had his moments during his time at Anfield - a cracker against Bordeaux in the Europa League, an spectacular scissor kick against Manchester United at Old Trafford - but these moments were all too few. Liverpool did at least manage to cut their losses, selling Benteke to Crystal Palace for £27m in 2016.
9. Juan Sebastian Verón (Lazio to Manchester United)
Fee/Transfer Window: £24.3m (Summer 2001)
Manchester United paid a British record fee to sign Juan Sebastian Verón from Lazio in 2001, and it seemed like good business when he hit the ground running with three goals in his first four Premier League outings. But the pace of English football soon took its toll, and Verón's performances took a nosedive.
8. Jonathan Woodgate (Newcastle to Real Madrid)
Fee/Transfer Window: £13.4m (Summer 2004)
Some players have their careers disrupted by injury; Jonathan Woodgate's career was one long injury disrupted by occasional periods of fitness. To the surprise of absolutely nobody, Woodgate got injured at the end of the 2003/04 season, but that didn't prevent Real Madrid from signing him that summer.
7. Angel Di Maria (Real Madrid to Manchester United)
Fee/Transfer Window: £59.7m (Summer 2014)
He started brightly, winning Manchester United's player and goal of the month awards for September, but that soon trailed off and he left after just one season for a loss of around £15m. He is now an integral and prolific player for PSG, that one-year spell in England being an anomalous blip in his career.
6. Gaizka Mendieta (Valencia to Lazio)
Fee/Transfer Window: €47.7m (Summer 2001)
There was a time when Valencia were considered one of the best teams in Europe, and Gaizka Mendieta was their beating heart. He was named Best Midfielder in Europe by UEFA two years on the trot, and when Lazio signed him in 2001, they made him the sixth most expensive player of all time.
Mendieta had been a prolific goalscorer towards the end of his time at the Mestalla, but he failed to hit the target once in 31 appearances for the Biancocelesti, who sold him to Barcelona after one season. He ended his career with Middlesbrough, those days of Champions League stardom long forgotten.
5. Jackson Martinez (Porto to Atletico Madrid)
Fee/Transfer Window: €35m (Summer 2015)
Atletico signed him for a similar fee to Falcao, but that was where the symmetry ended. Martinez scored just twice in 15 La Liga appearances, but his biggest sin was a lack of commitment - unforgivable in the eyes of Diego Simeone. He was shipped off to China after one season and hasn't been heard from since (not in a sinister way).
4. Andriy Shevchenko (Milan to Chelsea)
Fee/Transfer Window: £30m (Summer 2006)
Fee/Transfer Window: £30m (Summer 2006)
But Shevchenko's ageing limbs and the pace of English football did not agree with one another. He found the net just nine times in the Premier League before retracing his steps to Milan and Dynamo Kiev as his brilliant career sadly petered out.
3. Carlos Tevez (Boca Juniors to Shanghai Shenhua)
Fee/Transfer Window: £71.6m* (January 2017)
*fee reported by The Guardian
Shenhua were hoping that Tevez would help them win a first league title since 1995, but Tevez had different priorities - he later described his time in China as a 'holiday'. He scored four goals in 20 appearances and was accused of being overweight. Shenhua finished 11th, and Tevez rejoined Boca for a huge loss.
2. Fernando Torres (Liverpool to Chelsea)
Fee/Transfer Window: £50m (January 2011)
Torres scored 45 times for Chelsea, including the goal which confirmed their place in the 2012 Champions League final, but he never scored more than eight goals in a Premier League season at Stamford Bridge before returning home to Spain in 2014.
1. Andy Carroll (Newcastle to Liverpool)
Fee/Transfer Window: £35m (January 2011)
The panic buy to end all panic buys. It wasn't that Andy Carroll was a bad striker - he'd scored 11 goals in 19 appearances for Newcastle since helping them return to the Premier League - but it was such an obvious case of a square peg fitting a round hole, and showed how poorly prepared Liverpool were for the sale of Fernando Torres.