Join Date: May 2009
Location: Death Valley, USA
I recommend that you look for a good, used late 90's steel mountain bike from Specialized, Trek, or another quality maker. Those bikes are hardtails without front shocks, and are very rugged and versatile. With careful shopping, you can pick up a bike that's better than anything you're looking at, for well under $200 - more like $100 - $150. Budget the rest of your funds for a thorough tune-up by your local bike shop (LBS), some good shoes, and a maybe change-out on the saddle, which you can do later if needed.
Whenever anyone asks me for a bike recommendation under $500, I always suggest that they look at something used rather than new. Your money just goes so much farther.