I am hesitant to comment on this thread as it seems so well covered so far.
I will only re-iterate what I have offered many times in the past. Practice is what makes for effectiveness of a weapon (of which accuracy is key). You must learn the tendencies and idiosyncrasies of the weapon being operated. You must rehearse and memorize the position of the operator in relation to the weapon, the two sight points and your point of reference on the target. Body position and sight picture. Highly practiced operators have so in grained the properties of all these factors that they are able to reestablish all pertinent muscle movements to instantly create a 10 point shot on target. This takes tens of thousands of rounds to achieve. It is unrealistic for most (read: all of us) but none the less, do what you can to be the best.
I'll give some props to the weapon and some to the ammo; they have a significant role to play in the equation (probably 15% each). I think it is primarily practice (70%).
Interesting read about the revolver auto debate. Kudos to you gents, very informative stuff. I have experience with some exceptionally 'smithed m1911s that were beyond compare accuracy wise. Everything wise really, except for capacity. I've also played with many off the shelf varieties of the m1911, kimbers, colts, remington rands, a singer (

), and plenty of 9mm autos, s&w, beretta, sig-sauer...Accuracy was sporadic and inconsistent. Each had its own oddities, but all were able to kill out to 25 feet, once doped in, no problem.
I have yet to fire a revolver that took 'much getting used to.' They've all been relatively accurate, and consistently so across most variations.
What is it I'm trying to say...hmmm?
Without practice, I think I'd select a revolver. However since to me this is unthinkable, I would obviously select an automatic. Strange dilemma.
my thoughts,
-bear