I would like to just add a name here that has not been mentioned. He should be an easy tie for 2nd or 3rd place (behind Gavin)
ArtForz
We wouldn't have scrypt anything without him. (E.G no LTC) Not to mention various critical bugs solved for BTC.
Is this the guy who had closed GPU and FPGA miners before the public, opensource ones? Isn't Bitcoin all about open source?