everything looks great. i'm not familiar with the powersupply however.. but it should be good.
just some advice.. don't buy the 7800gtx, buy the 7900gt. its cheaper and performs better.. (or if you ahve the money, buy the 7900gtx). 7800 is last generation and they're prices haven't dropped.. so 7900 series is definitely the way to go.
may i also recommend that you up your processor to a 3700+ san diego, or, if you have the funds (maybe if you get 7900gt you'll save up!!) get the X2 3800+ dual core. very good value.
and your ram.. will that be just 1 stick? or 2 X 512? because with 2 identical sticks you get dual channel configuration..
will you be buying your pats from newegg?
"Is virtue a thing remote? I wish to be virtuous, and lo! Virtue is at hand." -Confucius