my paramilitary--even though I used to diss the compression lock, it is a knife that I think can take a lot of abuse and has a very practical blade shape. Horribly high pocket carry, however.
Being that it is only one Spyderco, not only one knife, I'm going to go with my Spyderhawk H1 Salt SE. I've kept a hawkbill on me for 8 years now and Spyderco makes them right!
Right now with the knives i actually have i would say the S90V manix 2. It's a hard choice but thats what i'd pick. Of course the S90V mule is a pretty close second. Just the manix 2 is easier to carry and conceal if needed