What video card (pci-e) would run flight simulator x very nicely at an exceptional price?

my current operating system is windows xp media center pentium d 3.0 ghz processor, 2 gigs or ram, nvidia 6600le video card, my motherboard is maxed out with ram.|||FSX is a very graphic intensive piece of software. I have tried to run it on a 7300gt256mb and it was choppy as all get out. I have a much better system and a 8800gts512mb now and I can run it on pretty high settings in dx9 and dx10. I would think that the main problem would be your processor, any decent vid card out there today will be bottlenecked by your processor, but its worth a try. you can always upgrade. good luck