2nd the ATI 5770 GPU, it is a better GPU at a lower price.
I would hold off on a sound card. Onboard sound now-a-days is very good. I would try it first and add the sound card if you don't like the sound quality.
I agree with the Samsung Spinpoint F3 1TB. It is a faster hard drive because it is based off of two 500GB platters vs four 250GB platters. Larger platter size increases your speed. The F3 rivils or beats the speeds of the VRaptor, plus at a lower cost. It would be my choice if not getting a SSD or the WD 2TB Black hard drive. I'm not a fan of a RAID setup because the increase risk of data loss. Two F3's in RAID0 will beat the VRaptor but I don't see a need for you to do that... IMO.