Ok, well..someone has the be the bearer of bad news. The 7900gt, shame it died on you, was a great dx9 card. It's good to have a newer dx10 card, but, if you are determined to jump in to dx10 gaming, you should start w/ atleast the 8800 series. In terms of gaming with the 8500 gt, it's great that it comes w/ 512mb of memory, but at this point, that's just there to make it enticing.
Large video memory is great if you're playing at high rez, but with an 8500, it likely won't happen as your framerates would be in the 10-15fps. What likely will happen, or what they did, was strap on the extra memory so it became a good option for basic computer use. It's a great card if all you're doing is general pc stuff: Email, websites and video should be great even at high resolutions.
If you are serious about gaming, i'd look into sending it back and getting some type of credit and going for a better card and paying the difference. It's really the only way to go. I been doing some research, the 8500 should handle WoW ok, but there are several reports of users having issues w/ the 8500 and the new patch for WoW. It's true the 8600 is now @ a great price point, but if you want any type of future gaming, you should go for an 8800 gt 512mb or better. As a gamer, this would be my suggestion. WoW isn't heavily intensive on the gpu, but games like crysis, on a 8500, while it would run them, you'd lose the main point of a game like Crysis because you'd have to turn most of the features which make it what it is, down to low.
