XFX Radeon 5830
 

Even with the limited adjustments available within the CCC's Overdrive utility, I was still able to max the GPU's clock speed in a matter of minutes and get the RAM to an excellent overclock rather expediantly as well. Throw in a free copy of Aliens vs. Predator and really, there is not to much to say about this card other than the XFX Radeon HD5830 is without doubt the card to have in its price range!

http://www.overclockersclub.com/reviews/xfx_5830/