#2 Cristiano Ronaldo

The Portuguese superstar could have been playing at Arsenal instead of Manchester United and Real Madrid had Wenger moved a little quicker for Cristiano Ronaldo's signature.
Ronaldo was discovered by Arsenal scout Damien Comolli back in 2000 during a youth tournament in France - he immediately informed Arsene Wenger about the young Portuguese wonder-kid.
CR7 twice visited Arsenal's training ground and even met his idol Thierry Henry - but the transfer ultimately fell through when Wenger failed to collect funds for the transfer.
A few months later Sporting Lisbon played Manchester United and Ronaldo went on to destroy the Red Devils, catching the eye of Sir Alex Ferguson in the process - and the rest, as they say, is history.