I like the feel and look of rosewood. I've had maple, rosewood, ebony, and carbon-fiber.
Tonally, it depends on the instrument. For a MM bass, I'd want rosewood to balance the aggression from the bridge humbucker. On my Taylor acoustic (guitar), I like the tight brightness of the ebony, to balance with the jumbo mahogany body.
I really do like carbon-fiber, as well. It's very clean sounding (for bending, glissandos, etc) and responds extremely evenly (dynamic changes), and has a very consistent tone across the board (ha ha).
By the way, I've noticed that a lot of people say "graphite" when they're talking about guitar fretboard alternatives to wood. I've never actually seen or heard of a graphite fretboard. Ebanol, carbon-fiber, plastics composite (Ovation), sure... but are there really guitars made of graphite? I thought graphite was a form of carbon, like they use in pencil "lead." I mean, yes, graphite, in its isotropic form, and synthesized, can be carbon-fiber. But then, why not just call it carbon-fiber? That's like saying that that your stainless-steel saddles are made of chromium - while technically true, it's misleading and not the best term for it.
Not to rip on you, I'm just curious why everybody calls it graphite when Modulus, Ovation, etc call it something else.
I guess there's Moses Graphite... but they're just silly...
Dave