I'm a KA-BAR fan. My favorite folding knife is one of their mule series knives with a tanto point blade. It keeps an edge well, and can cut, pry, and stab about anything. I've used it is as a can opener, small pry bar, skinning knife, and even an ax (hitting the back of the blade with a hammer). It's still in amazingly good shape.
My favorite fixed-blade knife is the USMC knife KA-BAR makes. It's just nice sized, has great balance, and will get and stay sharp enough to shave with. I've killed a bunch of pigs with it, and also some coons and other critters the dogs catch.
Just bought one of the zombie killer knives from KA-BAR. It looks a little radical, but for pig work, I like the size and the green handle makes it a lot easier to spot if I accidentally drop it in the dark. Whereas the USMC knife is better for stabbing the pig, this one has enough size and heft behind the blade to deal a fatal slice.