Thanks Pendragon for the quick reply!
A couple more questions, if you don't mind:
I have read both in your posts in this thread as well as from other sources that the 6870 produces a lot of noise, and I was wondering if there was another card you might recommend in the same price range with comparable performance. Having never heard it in person I don't know if it would get on my nerves or not, but if you think the noise is bearable in exchange for the card's performance, I doubt it'll be too big of a problem.
I'd considered another card, the EVGA Geforce 550 ti, but wasn't sure if the fact that it was a 192-bit card, as opposed to the 6870's 256-bit interface, would cause too big a difference in performance. The research I've done comparing the two seems to indicate that the 6870 is better, but I may well have missed something. Which do you think would perform better, particularly in ArmA 2?
The case I planned to use is the Thermaltake V3 Black Edition http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=5520044&Sku=T925-3018&SRCCODE=LINKSHARE&cm_mmc_o=-ddCjC1bELltzywCjC-d2CjCdwwp&AffiliateID=iFudSkud_Rc-h51AXcdtcr69Ae3_IDlwbQ. It seemed like a decent enough case with several mounts for fans and a fair amount of space.
In regards to the motherboard I chose, I actually didn't realize it had an integrated graphics unit installed, haha. I chose it largely because I saw a bundle for it and the processor on tigerdirect that could save me a couple bucks (as opposed to buying each separately) and after looking into what people seemed to think of it, it sounded like a solid board. Much thanks for catching that and also for your recommendations!
By the way, the power supply you recommended is also cheaper, in addition to being better, than the one I'd been looking at before. So a big thank you there :)
Thanks again!