it depends what you want, but I don't think you'll be happy with it overall
honestly it's gonna be hard to find a decent pre-built in that price range. at least something that I would feel comfortable recommending for modern gaming (aka keeping up with next gen consoles that are right around the corner. I'm sure plenty of cheap pre-builts could run circles around a ps3/360, but that's kinda irrelevant at this point)
you really should build your own. chances are you're gonna have to get in that box and do something eventually anyway. it's not that hard, and plenty of people can and will help you out