I would say something completely different tbh.
Get an i7 920 and get an all in 1 watercooling kit, overclock to 4ghz.
get 2 amd 6870's OR 2 470's overall the 6870's scale better due to crossfire but if you go for a single card the 470 beats it, iirc. Power supply is nice, stick with that its all you'll need, only thing i can suggest is getting asus mobo and GPU, the overclocking tool is nice and simple.
ram with with the i7 920 you can go for some nice tripple chanel, 6gb will be enough for your needs, mobo you can go for anything decent from the p6t series onwards, funds permiting.
this is similar to my build apart from i currently have a gtx 295 (which im selling to fund for a gtx580).
all in all a good build, may be worth while ditching one of your graphics cards and add in there a nice SSD, all depends but i would deffinatly think about a SSD.
One other thing is also your case, aim towards a nice one for air flow, im currently using an antec df85 which has one of the best air cooling on the market.
With great power comes great heat, COOL IT.