$250 USD will easily get you into an X1800 series card, which will have more power than the X800 series.
Figure the X800 series has 16 pixel pipelines, 256 bit memory interface, but lacks SM3.0 and FP16 blends.
The X1800 has 16 pixel pipelines, additional pixel shader pipelines (48) for modern games such as Oblivion, can do SM3.0/FP16 blends and has higher memory bandwidth.
So for a small difference in price, you get a lot more performance, more shader performance for modern games, plus SM 3.0 + HDR support. Better choice for the $$.
Not to say the X800s arent awesome cards. I run these in most all my AGP based systems as they also have 16 pipelines + 256 bit memory interface.