I voted Ruger... the Rugers I have shot, and own, have not been the best looking guns (except maybe the New Vaquero), but I have yet to curse one for failing, or have parts work thier way loose at the wrong time, or lock up and not fire at all. Ruger guns are just rugged.
S&W would have been the closest (and I mean VERY close) second vote for me - all my S&W revolvers are gems, but they do shed parts if not watched carefully or enhanced with Loc-Tite. I carry a 442 every day, so I am willing to bet my life on S&W. I am also beginning to really trust my M&P as well.
Colts are great, but I know my Python is a high-toned bitch if it is mis-treated, and the SIG has jammed, although rarely. I do not own a Springfield, so no vote possible there.
Just my opinions, of course, friends.
-Dave