Honestly, don't.
From what I've heard, the Radeon's have excellent picture quality.
As opposed to any GF card which doesn't match the quality.
(Has something to do with the colors I think /pixels?)
For the cost - wait.
For the performance gain - buy
Price / Performance - iffy, wait
It is a lot of $ to shell out.
Now the Ti 4200 series - price/performance/cost -
Might be worth waiting for.
I was between a hard spot & a rock
and needed something - now.
I couldn't justify buying a 8500 for big bucks (offline)
and having it outdated even more in 6 months, having it go into my "new" DDR/H20 system. So I did pay dearly for it. But I won't have to upgrade it in a year either.
Good Luck.