I personally carry an Emerson CQC-7 Wave. I'm telling you guys, it really is the best knive design I've ever seen. the Wave feature means ther is a little hook at the back of the blade, when you pull it out of your pocket, the little hook catches the corner of your pants, and flips the blade open.
The best part??? I got mine at a pawn shop for $18, pretty good for a $200 brand new knive. Some idiot at the shop had no idea what he had