I'm 23.
I cannot pick just one handle material.
I like figured woods. Bird's Eye Maple, Quince, Thuya Burl, and Maple Burl are my favorites.
I also like good-looking synthetics. Carbon Fiber, Micarta, and G-10. Well, blasted G-10 doesn't look very good, but it feels good. Polished G-10 looks good.
At the moment, I am really liking Micarta in various colors.
I also think I have a titanium fetish.
I am not a big fan of FRN, stag, kraton, or "boring" woods.