It may not look good but it's a really good performing case, one of the best for the price plus you may want the room for your cards.Another two to consider are the Antec 902(which i have, it can manage a 5870 but a 5970 is a struggle.) and the Lancool Dragon-Lord K62.
I said that res because that one plus 1920x1080 seem to be most common people game at now also the 5850 handles any game at that res with 4xaa or more on with ease.(except Crysis but still plays it very good but care about one game.)