If I had to choose one of the 4, it would be the 1911, what can I say, its been battle tested and proven. But from my stash, I'd go with my fullsize HK USP 45 or my Springfield XD, both have been put through hell for torture testing with high grades.
Back a few years ago I might have said Glock 19 because of the mags (also use the 17 mags) and the fact that lots of cops seemed to be carrying them. Now though it seems like most are carrying the .40s&ws. That being said, I would go with the Beretta 92FS because there are a lot of them out there and lots of 9mm ammo out there.
Any poll like this that doesn't have a SIG as a possible choice seems like a joke to me. That being said, I chose the G22. I've already got one and I love it.