I really want to get a new video card (using radeon 8500) but I am worried any offering now will not be good enough for the eagerly awaited doom 3.

I'm in exactly the same boat. I want to upgrade my mobo and video card, but I want to find out what the best combination of those two things will be for running Doom 3. I want to be able to run that game with everything cranked so I can see every creepy effect it has to offer.