Most often lately, it's a Glock 27 with factory tritium sights and a stainless guide rod, loaded with Winchester Ranger T's.
Though it's sometimes replaced and/or accompanied by my Glock 30 or 23.. or my Kel Tec P32... sometimes my Sig P245 or Ruger P97 (if I'm in a 45 cal mood), or my Galesi 25 in a pocket holster. I've recently gotten one of those NAA mini revolvers in .22 which I toss in my pocket, too.
And sometimes I'm in a revolver mood, so I break out the Taurus 85UL or the Rossy .357 snub.
Yep, I'm a gun whore.