T-shirt weather: Usually a S&W M637 with Hornady FTX in a pocket. The little snubbie may get some competition from the Walther PK380 with 102-grain Remington Golden Sabers when I get a good IWB holster.
Heavier shirt weather: Beretta FS84 Cheetah with 102 Remington Golden Sabers in an Uncle Mike's IWB holster.
Jacket weather: Beretta PX4 Storm with 147-grain Remington Golden Sabers in a Fobus holster or FN-Herstal FNP-9 in shoulder rig.
Now and then: S&W M60 3-inch and S&W M637 for New York reload.
Also Gerber E-Z Out Jr., Victorinox Swiss Army Knife, cell phone, key chain with mini-flashlight, and the usual (wallet, handkerchief, comb, etc.).
When it's really cold or when I can OC, I have a Bianchi rig with holster for the PX4, mag pouches and an 8.5-inch Mini Maglite. I have a heavy black duster and I could probably CC a bazooka underneath it.