See if you can find somewhere where you can test ride something like this: http://www.giant-bicycles.com/en-us/...x4/7321/44098/
Giant gives you a pretty good amount of bang for your buck, and they offer a full suspension bike in your price range (Trek and Specialized's entry level models are a couple of hundred dollars more). You get Shimano's entry level hydraulics on there. And while the drivetrain isn't great (Alivio/Deore mix), the fork (RockShox Tora) isn't bad at all. 5 inches of travel, so it's considered an all-around trail bike.

Also make sure you check out the second tier companies, like Jamis, Rocky Mountain, Kona, GT, Haro, and the like, because they often offer great value for less money than you'd pay for something from one of the big boys or for a boutique bike.

And no matter what, test out the bike before you buy. No sense dropping that kind of money on a bike that doesn't fit right.