I have the Nvidia 8800GTS, and I want to upgrade. My Motherboard is an Asus P5N-E SLI. So basically I was thinking about the Radeon ATI 4870 card, but I really don't know alot about GPU's. My budget is no more then $200 at max.
Alright. The HD4870 wouldn't have been a huge upgrade over the 512mb version which is much more powerful.
I would probably recommend either an HD5770 or HD4890 with that budget. However what is appropriate for you depends highly on both your monitor's native resolution and the specifications of your power supply.
I don’t recommend upgrading your graphics card unless the replacement card is at least three tiers higher. Otherwise, the upgrade is somewhat parallel and you may not notice a worthwhile difference in performance.
3 teirs up puts you at the 9800 GTX GTS 250 range
At your resolution, anything more than that would be overkill.
An 8800GTS 320mb is on par with a 9600 GSO which I've used a good bit at similar resolution. It's a good card for that but I wouldn't call it great. He should definitely see a noticeable difference in a lot of current games and probably in most if he wants to max out AA.
He hasn't mentioned what he is playing but he came here for advice on upgrading. I don't see why he would do that unless he wanting better performance in the games he is playing. Can you think of another reason?
Bottlenecking hasn't been mention of course because he hasn't told us his CPU which is a decent question actually.
You should really figure out if you are going to upgrade the monitor before buying a new card. If you really aren't sure but you might then go for the HD5770 as it well do pretty well even up to 1920x1080.