The Specialized Hard Rock Sport is the house Clyde bike and in your price range. My wife has a newer Trek 820 and I would not recomend it for off road use. The stock fork is crap and the geometry makes the bike pretty squirly on anything that resembles a downhill. The older rigid fork ones are a little better. You might want to check out Craigslist in your area. You could get a nicer bike than you could afford new that has just been sitting in someones garage for two years. If you go used try to get a 19 or 20 inch frame.