As I stated in another thread, I carry a S&W 442 with Hogue Monogrips, but daily practice with a Crosman 357 pellet gun (copy of a Colt Python, with plastic "Hogue Monogrips", 4" barrel though) in my spare bedroom "range". Not only do I use a (accurate) pellet gun for economic reasons, but also because the Winter weather here in Mississippi has got to be the worst I have ever seen (cold temps in the teens, heavy rain, annoying snow, thick mud, high winds, etc), so going to the outdoor club is usually out of the question. But when I can go to the range, I shoot another cheap practice solution: a .22LR Taurus 990 Tracker (Hogue Monogrips, 4" barrel). I also shoot a Colt .357 Python (Hogue Monogrips, 4" barrel) at IPSC shoots.
I shoot my 15oz S&W 442 carry gun whenever I feel like damaging my hands.
I figure that the Monogrips, and with all of my practice pieces being revolvers, that they have enough commonality so as to help my shooting skills with my 442 CCW piece. (Just wish the Python and the Crosman loaded ammo the same way as the 442, but ya can't have everything...).
So, what do you practice your CCW shooting skills with?