Beginning with Eric Cantona and ending with Robin van Persie, Ferguson has usually spent money wisely at Old Trafford, although there have been some flops.
Here are some of the best and worst Ferguson signings.
BEST
Eric Cantona
Signed from bitter rivals Leeds United in 1992, the feisty French maverick was influential in United winning the title a year later. Cantona went on to win three more titles and remains a true United icon.
Peter Schmeichel
A colossus between the posts, the Denmark international signed from Brondby in 1991 will go down as one of United's greatest goalkeepers. Fearless and demonstrative, Schmeichel led from the back for eight years.
Cristiano Ronaldo
When Ferguson signed Ronaldo for £12 million from Sporting Lisbon in 2003 to replace David Beckham, many questioned his judgement but the Scot moulded him from a flashy winger into a prolific goalscorer who netted 42 times in the 2007-08 season. Sold to Real Madrid for £80 million.
Robin van Persie
After losing out on the Premier League title to Manchester City last season, Ferguson beat their bitter local rivals to the signing of the Dutch striker from Arsenal and his 25 league goals helped United cruise to this season's championship.
Roy Keane
Signed to replace Bryan Robson in United's midfield engine room, Republic of Ireland midfielder Keane stamped his authority on the side throughout the 1990s, leading his team mates by example. His rivalry with Arsenal's Patrick Vieira was pure box office.
Wayne Rooney
Rooney exploded on to the scene at Everton in 2002 and the young striker was lured to United in 2004 for £25 million. Scored a hat-trick on his debut in the Champions League and is now approaching 150 goals for the club.
Rio Ferdinand
A thoroughbred among defenders, Ferdinand's calmness on the ball prompted Ferguson to sign him from Leeds for £30 million in 2002 and he has been a key part of United's defence ever since. Ferguson stood by him when he was suspended for missing a drugs test in 2003.
Nemanja Vidic
Not well known before his move to United in 2006, the Serb has formed a telepathic understanding with Ferdinand and is now the club captain.
Ruud van Nistelrooy
The combative Dutchman scored 95 goals in 150 league games for United after signing from PSV Eindhoven in 2001 fo
