Depending on season, mood and style:
Star PD .45 (aluminum frame, SA)
Star BKM 9mm (aluminum frame, SA)
Colt "Pony" Pocketlite .380 (aluminum frame, light DAO thanks to a previous owner)
I have carried others but these three are a good compromise of weight, size, shootability and dependability. The 9mm is my usual; underpowered by modern standards but I'm most accurate with it.