I'm also a knife fan.
I've had some training in both disarming knife-wielding opponents, and in use of a knife (based on systems from the Philippines). The combination of both makes me more afraid to try disarming a knife-wielding opponent than I would be disarming a gun-wielding opponent.
Lately I am gravitating towards mid-priced offerings. I want more durability than the cheap knockoffs, but many of the $150+ priced blades aren't so much better that they are worth the extra cost, unless they have some very unique advantage (extra-good carry system, etc.). My favorite is a Cold Steel Recon 1 (half-serrated spear point), or when I need something smaller, a Benchmade Griptillian or Mini-Griptillian. Cold Steel's "Proof' and "More Proof" videos are a must-see, although "More Proof is unnecessarily long. I'm looking at the Spyderco Dodo for when an even smaller blade is called for.
I avoid most liner locks like the plague. I've had some expensive ones wear out quickly. I have some acquaintances who have had waved Emerson knives converted by other knifemakers to frame locks.
For fixed blades, Mickey Yurco makes some of the best and most reasonably priced I have seen. He also has a good feel for truly practical sheaths. Bud Nealy's MCS sheath system is also really nice, and his Pesh Kabz was my first "custom" knife.