I'll always be partial to Roger Moore since he's the Bond I grew up with and "defined" the role in my eyes. Yeah, naysayers will say "But Connery...." but the fact of the matter is, the James Bond role was originally written for Roger Moore who had to turn down doing Dr. No because of other commitments at the time. Thus, the role was given to Connery instead, the second choice.
All that said, Craig is a very close second. I'd say Lazenby next, then Connery, then Brosnan, then Dalton.