Mastersmith's is the way to go. Great atmosphere for knife browsing. He has a wide range from production pieces to high-end folders, fixed blades and swords. Bill will make you feel at home. I was also lucky enough to meet JD Smith there one afternoon.
Paragon has a pretty good selection too, both production and custom, but its much more impersonal and some of the people that work there aren't very knowledgable about the merchandise.