I, personally, would recommend Spyderco, Benchmade, Kershaw, and Zero Tolerance. There are LOTS of other brands out there, but those four have everything covered from inexpensive $25-30 knives, all the way through a few hundred bucks.
From Spyderco, check out the Stretch, Delica, Endura, or ParaMilitary 2 (often abbreviated as PM2). From Benchmade, a Griptilian would serve you very well, as would a 710, a Presidio Ultra, or a Barrage. The Grip is kind of the gateway Benchmade.
From Kershaw, there are too many to list! The Leek and Blur are both excellent folders.
And from ZT, a ZT0350 is a good place to start, as would a used 0560/0561 if you snag a used one.
PLENTY of other options from these companies, however.
A real sleeper for me, though, was the RAT-1 folder. I bought a used one off the Exchange a few years back, an it's the smoothest, most amazing $20 knife I've ever owned. Highly recommended if you also want a little beater knife!
Whatever you go with, welcome aboard, and hide your billfold!!!
