So I've got a 3 year old system that has a socket 939 mobo, 2 gigs of PC3200 DDR RAM, an Athlon 64 X2 4200 processor, and an ATI X850 XT video card.
I'm looking to stretch out the system life a little longer to be able to play Operation Flashpoint 2, Darkfall, and Dragon Age (medium settings would be fine for all). What video card would give me the best bang for my buck for this sytem, keeping in mind that I really don't plan to make any more upgrades after the video card. Once I can't play any new games at medium settings on it I'll just spring for a new system.
I had the extact setup as you do. I upgraded to a visiontek ati 4850, about 170 bucks or less, and got 8900 points in 3dmark06. I could play almost any new game out there on high settings and it ran very smooth.
It's a leap up from what you have, and if your budget and/or PSU is limited, it could be a viable choice. Otherwise, a 48x0 will be even better. What brand and model of PSU do you have? A 4850 requires 450W, assuming it is a good one.