An ATI Radeon 9800 Pro 128MB version is going to run you a tad over $300 now, buying online. The Radeon 9600 Pro is even cheeper, though it will probably not last as long. I personally now go for the big jumps from time to time instead of doing rapid upgrades that aren't the best in their class at the time. This allows me to enjoy high quality gaming for a decent amount of time, and not deal with changes to my computer as often. Sure, high end video cards are more expensive then consoles, but they are also usually more complex. Plus video cards don't have game sales to fall back on to lower prices.

While the Radeon 9800 Pro is not going to be better then the GeForce FX 5900 Ultra in Doom 3, it will probably be better with most other games. Reason being, it seems ATI followed the standards a bit better then NVidia this round, thus games without hundreds of man hours behind their optimization for one particular card* will do better on the DX9 supporting Radeon boards.

* John Carmack has spent quite a bit of time creating a specific rendering path for the NV3x cards in the Doom 3 engine. On the ATI front, their higher end cards do just fine with the standard Open GL paths programmed into Doom 3, so no specific R300 path exists, and the peformance difference probably would not be worth the time.