S&W 686 would be my choice, but that is what I'm in the hunt for next after I get a shotgun so I guess that makes me partial to those. So far the hunt for a 4' 686 has turned up jack crap so I may go with a GP100 since they seem to be more common. A Glock 19 is also on my short list as well so I guess I'm partial to that one as well lol. I'm useless in this discussion because I like/want them all.
If you held me down and forced me to chose one or the other I'd go 686 though. Either way any of those choices would be fantastic.