The Tops "Felony Stop". It has only one purpose, so most EDCers will ignore it, but for its intended role, I think it would be hard to beat. It should go without saying, but you should never want to be in a knife fight; also, this is likely of questionable legality in many jurisdictions, so...
IF I had ever purchased one, I would have gotten it at KnifeWorks.
I get asked about this knife all the time so I guess it's time I elaborate a bit. This is Enzo Birk 75, I traded this away recently, even though I liked it a lot. This is an excellent, very high quality knife. S30V blade, Ti bolsters, CF handles, full stainless steel construction, all this for 150$ or so before shipping (and taxes, depending where you live). Made in Finland. Pros: scary sharp, excellent fit and finish, great blade shape, awesome clip, very comfortable, great price. Cons: liners are not skeletonized, difficult to disengage liner lock once closed - that's all of the cons :) You can buy it HERE.