I was running an ATI Radeon X800 XL 256 MB AGP card, but the fan crapped out recently and I sent it to ATI for warranty service. I am considering going with something new entirely. I want exceptional gaming performance, but am only looking to spend about $150-300. I am looking for great performance on high detail settings for BOTH Half-Life 2 and Doom 3.
The GF7600GT is better, but not worth an 'upgrade'. But since your previous card crapped out and it's just a straight buy, not upgrade, then the GF7600GT is your best option, and it competes well witht eh X850XTPE but with some added useable features.
And if I'm not mistaken, the 7600gt will consume alot less power than the x850xt version (no added power connection needed). I'm also going to be in the market maybe for an AGP card, but not sure if I'm going to spend the $ for it yet
You mentioned the X1900, that is not an option for you since you are running AGP. The X1900 only comes in PCIe as far as I know.
I think that the X850XT PE would be sweet. Even the X850XT would be nice.
Neither would be a huge jump over what you have now but they would help.
It is true that the X850 series doesn't support Shader Model 3.0 but we don't know if you would benefit from that. Only certain games make use of those features because they are fairly new. They also require more GPU horsepower. If you will play games that use SM3, you must choose between having the best graphics or having higher framerates or higher resolutions.