First of all, I think that every actor who has played the part was competent. I like how they all brought their own different translations, both physically / body type / looks and acting, to the character.
My personal favorite is Dalton, I think he mixed the suave with the tough. I wish he would have had more and better stories, though I find his first movie to be thoroughly enjoyable. The skiing on the cello case scene is awesome. The last two Moore movies would have been better with Dalton.
I loved Lazenby, again he seemed to mix the suave debonaire Bond with the tough guy.
Connery originally defined the character on screen so it's tough to say exactly what he did best, but it all was good. Every other actor to play the part is by definition measured up to Connery's portrayal.
Brosnan was born to play the character. He was pretty much perfect IMO. Too bad he only got one really good story/script.
There are two Moores. The earlier, rougher, "Live and Let Die" Bond, and the older, more humor oriented "Moonraker" Bond. You can watch the transition. My favorite Moore movie is "Octopussy". The backgammon scene where he pulls out the fake Fabrege egg is perfect. He also was easily the best at delivering the "zingers" which I love (and which unfortuanely seem to have dissapeared - I haven't seen the new movie but from the reviews I'll wait for a rental). "It's not really in the wrist". Classic. I also love where he meets the local Indian BSS agent who plays the Bond theme for the snake on the riverside as a signal. A nod and a wink to the audience. - maybe the next poll should be what's your favorite movie?
It's a shame with Daniel Craig the producers seem to have forgotten what this movie series is supposed to be all about. Craig's bond is my least favorite, for the reason that EagleMoon describes.