Trek, Cannondale, Specialized, Kona, Giant, Gary Fischer are all good name brand bikes. Go to a local bike shop to get the bike. They`ll fit you to the proper size bike and will help you with any questions or problems you may have with the bike later on. Thats their job, they work with bikes, whereas someone in a dept store might not be as knowledgable. You can also repost this question in Sports>Cycling there are a lot of mtn bikers there but they`ll pretty much repeat what I just said.
