Fixed blade for me.
I occasionally carry a CRKT Stiff K.I.S.S. OWB. I usually carry a Gerber Guardian Backup IWB.

I like the Gerber because it's cheap, the sheath has adjustable retention, can be carried IWB, OWB or on Molle, and the clip has a small hook on the bottom that prevents the sheath from coming off as you draw the knife. The CRKT is a great blade. However, it has to be carried between my belt and pants, so I can tighten down on it with the belt. If I don't, the sheath will come out with the draw.

I don't know how well the Gerber will hold an edge, but I only carry it as a last ditch defensive tool. It has a 3.4" blade, I believe. It's SUPER light weight too.