I agree with the above recommendations. Seagate is currently having major problems with the 7200.11 line of drives. The WD Black drive is much better.
Raidmax PSU's are a definite no-no.
You also don't need DDR2 1066 RAM. The Q9550 won't reach the high FSB required by DDR2 1066 RAM. Pick up a high-quality DDR2 800 kit that runs at 1.8v with tight timings. This one is about as good as it gets: