For finish, there is nothing better than wood stained to match your furniture. Obviously something like what RBH offers, with their cinemasite especially, is awesome. I also like SVS who offers the entire line of minwax (I believe) stains for their top sub(s). Customizability is always nice, and as a consumer, it really makes me feel like the company takes personal care of my needs.
Since these are higher priced speakers, and not everyone can afford them, for lower priced speakers, if the wood finish (or wood-colored finish... evil eye towards axiom and their vinyl
) looks incredibly cheesy or does not fit, a black matte or piano finish is always nice because it will blend in with anything. The only downside is that they are "just another pair of speakers" to the innocent observer, as opposed to speakers that directly match your wood shelves or trim or whatever, which has a certain "wow" effect and gives off the illusion of a very professional installation.