It's rare when you find one holster that will fit multiple handguns, but I discovered that the Galco Stow-N-Go will do just that.
For $25 (Cabelas) my S-N-G made to fit my Smith & Wesson J frame turns out to work well with everything from my Walther P22, my Beretta 85 (.380) and my Colt Combat Commander.
For the price and versatility this holster is pure WIN. I've found that secured over my right hip that the plastic belt clip will keep the holster secured to my jeans alone without a belt if on a rare occasion I'm not wearing one (quick run to the store, cutting the grass, etc).
There is no forward rake or cant just a straight up draw which aids in concealment, and the soft suede is uber comfortable. Over the Summer the wife and I drove out west and I wore my Combat Commander tucked inside this holster for the entire 18+ hour drive.
If you are in need of a multi-gun IWB holster or just one gun specific I definitely recommend Galco's Stow-N-Go.