On a using knife, for looks, I like bone. Just not bleached pure white, I prefer some mineral content, or age, to provide some color, and character. Second, for looks, is stacked leather. My favorite is the SOG S1, with Randall a close second. Or maybe it's the other way around?
For practicality, I like hard synthetics. Micarta, in some flavor, primarily. My EDC fixed blade is black/maple Richlite, similar to paper micarta, as I understand it, and it holds up quite well. I don't baby it, and it does get knocked around. But I appreciate the advantages of FRN, G-10, etc., particularly when it comes to grip texturing and handle shaping. Not a fan of kraton, or other semi-soft synthetics.
Wood handles, for me, depend on the knife. Some knives are, and look, great in wood, others I might prefer something more durable. I do have several wood handled blades, tho.