I like my X800 XL. (ATI original X800 XL PCIe). It really performs well.
It seemed like a good deal when I bought it for $280 in March 2005, and its price is less now.
Above, KillerPotato recommends waiting for the next generation of cards due soon. On the other hand, jfall above says to not wait.
If I was buying now, I'd learn what / when new cards will be out. I guess I'd probably wait for the new generation if it's not too long a time, because then you'd have a choice between either a cheaper X800 XL (prices will plumet then), or a new GPU design that might be lots better.