Good
Protech Whiskers BR-1 - My first auto, and the first knife I've owned that really amazed me. The sound feel/sound it makes when it closes is unlike anything I've ever experienced. It simply screams precision.
Spyderco Gayle Bradley - No other knife fits my hand as well as this knife using a saber grip. It also came frighteningly sharp from the factory, and the build quality still impresses me.
Sebenza 21 - It just feels different (in a good way) from any other knife I've owned. The pivot is incredibly smooth, the lockup is beyond solid, and I think it's one of the most beautifully designed folders I've seen.
Wenger Patriot - My first pocketknife. It was one of the first items I owned that was all metal, which really impressed upon me that it wasn't a toy.
Bad
CRKT Ed Halligan K.I.S.S. - Bought it on sale from somewhere, and hated it. Not sure I carried it more than once or twice. I'm not a a big fan of chisel grinds; maybe I just haven't found a good one yet.