The best wallet, IMHO, is not leather. It's the Spec Ops THE Mini wallet. I've had one for about a year, and it's everything I wanted in a wallet. The lifetime warranty leads me to believe it'll be the last wallet I every buy.

I wanted a wallet that was both thin and that I could carry as a regular wallet, but also carry it as a neck wallet. This way, I could easily carry my wallet when I didn't have any pockets (such as when working out away from home).