To a bike geek that is totally a loaded question, darn close to a troll. Are you looking to buy a new bike or pick one up on craigslist? If used any modern mountain bike would probably work. If you pick up a bicycling magazine there is usually a section in the back where they reccomend bikes for people that might give you some ideas about what to look at.
What we think, or what we know, or what we believe, is in the end, of little consequence. The only thing of consequence is what we do. -John Ruskin