There is a new speed king when it comes to video cards. Even better, the speed comes at a lower price. There are a variety of cards based on the ATI Radeon HD 5870 and all sport the same price of $399. Of those posting comments, the only negative seems to be the large size of the card at 11.5 inches long. So if you are going to get one, make sure you have room in your computer for it.
My preference in video cards has always been to get one from nVidia simply because their drivers have always had a “better reputation” than those of ATI. Of course this is all very subjective so I can’t make a personal judgment since I’ve not used an ATI card. If you are in the market for a new card, look at what is available and see what works best for you. Definitely this is a card that should be on your short list.