I going to agree with yumyumrocks on the PSU and the RAM. On the RAM you need to get it by 4/24 or it goes back to the regular price.
a modular PSU is nice to have and that one he linked is a good one and will look nice in the case you picked out.
I will disagree with yumyumrocks on SLI/CF, not every one needs it. a lot of games don't even support it and there a stability issues with running in SLi/CF. most people are better off without the headache. (My $0.02)
OK I've decided to get the Cooler Master PSU since it's only $4 than the one I picked when you count shipping. I was bit reluctant at first, as I've heard bad things about the CM brand of PSU.
About the ram, do I really need 8gb? I'm thinking about getting a 4gb pack and using the extra $40 on a better video card.
I like 8Gb of ram, granted it doesn't make games any fast, but it does cut down on swap file usage. If knocking it down to 4Gb's gets you a better GPU its a no brainer! at GTX 560Ti would be a great choice if you can fit it in the budget.
6870 is a great card, and well priced. I think the 5850 that i linked is a far better value, however. At $140 it is a steal. In fact, i think it is the best value available. It only suffers in its crossfire scaling, and even then its still good for the price. You can view the benchmarks for several games here: