Darrel's new integral-lock folder would easily be my first choice, assuming you're willing to spend that much. The other choice from Darrel is the Krait, which is also a hell of a knife, but kind of expensive.
Elishewitz's stuff is really nice too, he's long been one of my favorite knife designers. His liner locks are hit or miss in my experience. However, his customer service is good, and if you get a bad lock you can return it to him and he'll fix it up for ya.
Joe
jat@cup.hp.com