The Big Debate: Who has been the best summer signing?

I have had many conversations with friends in recent days about who has been the best summer signing by a Premier League team. The obvious ones are Robbie Keane to Liverpool, David Bentley to Tottenham, but what we want to know is, who do you think is has been the summers best signing?



Take into account, was the player value for money, will he improve the side he has moved to and most importantly did the side really need the player? Leave your comments and enjoy a good argument!