From what I can tell from this chart, this is the best bang for your buck

http://www.tomshardware.com/charts/gaming-graphics-charts-q3-2008/Assassins-Creed-v1.02,737.html

ATI Radeon HD 3850 CF

Cf means crossfire right? So the cf benchmark is based off 2 of these cards right?

http://www.newegg.com/Product/Product.aspx?Item=N82E16814140103

Im not expert im in the market for a video card, is there anything im missing?

I pretty much only game.
I currently use 1680x1050, will have much higher res later.
Looking to spend around 100$
Windows Xp sp3
Duo core
2 gig ddr2 ram

Will get more specs after I install my new mobo I cant access the computer atm.

I would also recommend the 4850. It's a card quite capable of playing your games and gives you room for upgrading your PC (Crossfire support).

Hmm how much better is 2x 3850 compared to the 1x 4850?

I was thinking when I upgrade again I can just buy 2x cheap cards again that combined are stronger then 1 good card.

Are those benchmarks I linked accurate at all?

If you're going with a higher resolution down the line neither of your choices will do much, maybe the 4850 can handle that.

Yes two 3850's will be slightly better but not enough to worry about. the way I see it is if you buy the 4850, It's going to give you room for upgrading later on.

Since you say you will be using a screen with a res of 1920x1080 or higher, you would need two HD 4830s or a single HD 4870 to get playable framerates. The HD 4850 cannot handle that high a res on its own.

Good points, however it turns out I need a new cpu, im going to get a 220$ quad core. So I am probably not going to get a video card for another month.

Current video card is 7600 nvidia gt, runs wow on the highest settings at good frames. Its a pretty low demanding game, but its the only newish game I play. I want another card so I can sample all the newer games with ease. Ill definitely be playing starcraft 2 and diablo 3 when they come out. Ill probably go with the 4870.