4) Cesc Fabregas
The Barca fans might claim Arsenal stole the midfield wonder but Wenger snatched up a teenage Cesc Fabregas for a minuscule amount from the Catalan giants when they stalled on giving him a contract.
Fabregas would go on to develop into one of the most accomplished creative midfielders in the world and one of, if not the best, in his position.
Whilst Wenger may always feel sorrow for the fact he couldn’t keep the Spaniard or build a title winning side with him at the core, he can stay safe with the knowledge he helped develop one of the modern game’s great talents.