The chaps over at Tech Report have put together a nice DOOM 3's performance comparison of various low-end, mid-range, and vintage graphics cards.

Here's an excerpt:
Moving to our assortment of current mid-range graphics cards, the GeForce FX 5900 XT is the clear choice for DOOM 3. ATI's Radeon 9600s just don't have it, and not even the eight-pipe Radeon 9500 Pro can bridge the gap. The only cards that give the 5900 XT a run for its money are the former DX9 flagships, the Radeon 9700 Pro and GeForce FX 5800 Ultra. The cards are pretty close in High Quality mode, but the 9700 Pro stumbles a little with Medium Quality and 4X antialiasing.