I had settled on the CRKT Ken Onion Ripple, and I'm glad to have two as they are currently out of stock.
It's slim (especially compared to the M16s I started with), carries easily, opens quickly, and cuts well enough. It was also fairly inexpensive, which is a bonus for a working knife.
ETA: I do have the stupid wantsies for one of those folding Gerber Applegate/Fairbain Covert knives, and will probably get one down the road Just Because.