Breakdaddy said:
I'm using a 9800xt and LOVING it. I've recommended ATI cards to my father and some friends and all of them that purchased one have thanked me for the suggestion. Having said that, the Deus Ex 2 engine is a system hog. You will want at least a 9600 128 meg and preferably a 9700 pro or better if you want to get the best out of this game. If your motherboard doesnt support 8x AGP it might be time to upgrade to a new mobo. Let's also not forget the cheapest and most oft-overlooked upgrade: ram. If you are not sporting at least 512 megs, upgrade NOW! This will invoke a mighty performance boost on almost any newer game. Going up to a gig of ram will also increase performance, but nowhere near as dramatically as the initial boost to 512 (which is the current "sweet spot" for gaming). Processor isnt as important as the video card and ram, but the newest games would be best served on at least a 1.5ghz platform. I know, I know, WAYYY more information than you asked for. I talk too much, it's a curse...
1) The difference between AGP 8x and 4x is nonexistent. There is no reason to buy a new motherboard just for 8x AGP. Of course, 8x AGP usually means the board is new, and a new board is often better than an old one, so that might actually be a good advise.
2) I agree with the 9800 XT, it's a fine card. I have three of them here, from ASUS, Abit and Hercules. The Abit one is by far the best of those three. However, I wouldn't recommend 9800XT to anyone, rather I would recommend the Radeon 9800 Pro which is far more reasonably priced. The 9800XT is one of those thing you buy because you know you need it, not because someone else tells you.
3) Gigs of RAM wont help you if it's, say, PC100 SDRAM.

If you have a motherboard that supports (dual channel) PC3200 DDR for instance then the speed will help you more than the amount. Otherwise yes, 512 MB is usually sufficient if you just play games.
4) The CPU _is_ important. Look here for instance.
This is 640x480 so a FX53 will not automatically give you 140 more FPS, but if we compare, say, an Athlon XP 1600+ with an Athlon 64 3400+ and the same high-end video card the XP proc will be the bottleneck.