depends on what sound you want. If you are looking for a mellow and warm sound with growl, all mahogany is hard to beat. If you're looking for a singing tone with lots of sustain then I'd suggest hard maple. Fingerboard material is very important as well, maple stains, rosewood can be eaten by roundwounds so I guess that leaves ebony, pau ferro or phenolic if you want to use rounds. If you prefer flats then rosewood should be fine.