Ive always been partial to horn or bone handles. Ive recently re-handled a few of my own knives with moose bone and am amazed at how nice it polishes.
Really boils down to personal preference, and if you are looking at the handle from a purely functional standpoint, or want a little class. I hear that some folks are putting rubber handles on filet knives...not real classy but durable with lots of grip for your hand.
Silvertp