[timgco]

It really depends on teh type of rides you'll be doing with it.

Those frames you pictured looked like downhill bikes.

In that price range, get a fron susp. bike only (as CO mentioned). You want to make sure you are getting some good components for your money. If you don;t you'll have a full susp. bike with busted parts and will end up spending outside your budget to keep it going.

Look into Specialized.