Impervious to the elements and designed for full size pistols, Fobus' new IWB holsters are an solid, affordable option.
The back of the holster is a flexible polymer designed to mold itself to the concealed carrier, while a rigid shell holds the firearm secure. Two sturdy polymer clips go over the waistband and belt, and are generously spaced on the holster to distribute the weight of the handgun.
This universal-fit holster is designed for full size handguns like the Glock G17 and Smith & Wesson M&P, but should work for most larger semi-automatics. I tested it on my G19, and it proved to be slightly too large to safely carry the Glock, so compact and mid-size pistols are most likely not good choices for the IWBL.