Graphics card of CPU upgrade?

[black-ops]

Hello all, Currently my system is using an Nvidia 8800 (getting old) and an E7200 which I don't know how old tech it's getting, either way I've managed to OC my E7200 to 3.1 Ghz, and my gpu is just well, lying about. I wanted to know what would be most advantageous to upgrade atm and looking at games like ArmaII, BF1943 etc. what you would recommend as an upgrade as opposed to my current hardware. Only one either graphics or CPU then i will buy the latter of the choice another time.
Thanks all!

 

[black-ops]

brilliant feedback guys, yes i heard arma was quite cpu intensive. I thought the 6700 was a cheaper version of the 6600 or am i thinking backwards aha =P?
Im currently running at 1280 x 1024 and don't really have an intensions shortly of getting a screen capable of higher res atm. So if i were to say anything better than the 6700 by say around £50 would you say thats worth it or is the 6700 the best for that margin? Same with the 4890?
Cheers.