Kershaw and Spyderco, for pretty much the same reasons: Near-perfect build quality (in my experience), very functional designs (more Spyderco than Kershaw, but true for both), outstanding customer service, great overall value.
I tend to give Spydercos as gifts for these same reasons... The last two knives I gifted to people were Spydies (a yellow Salt I PE for my surfer uncle and a Persistence for my step-brother), and I'm planning to give my apartment-mate a Centofante 3 for her birthday (she's a knife nut like me, but much less addicted).