Read the reviews on that hard drive pretty carefully... Some of the server drives are missing specific features found in consumer drives. For example, western digital has 2 models of server drives that make absolutely terrible consumer drives. One is targeted at RAID applications and the internal cache logic is significantly worse than normal when used as a standalone drive, and the other one doesn't fully or correctly implement S.M.A.R.T. standards so the drive temperature and health readings can cause some hardware or software to improperly fail out the drive, prevent it from going into sleep mode, or worse.
For that matter, the drives might simply be noisy and hot as heck if they use better bearings that last longer but make hideous noises and heat up more than consumer drives. That doesn't matter much in a server room with lots of forced air cooling and noisy fans, but it could matter a lot to a home user. Slower read/write arms might also last longer, and give much worse seek times. Again, not much of a problem in a server that might have several gigabytes of cache or use RAID arrays, but for a home user it would suck.
I don't know anything about that specific drive (except that it's about $10 more than an equivalent consumer drive ought to cost) but I've read reports of people getting burned by buying "server" hard drives that turn out to be either a lot slower than comparable consumer drives, or not suitable for what they end up being used for because they're not intended to be put into consumer level computers. So research it carefully before spending any money.
As for the vid card and PSU, I understand you have to set priorities. Again, make sure you have a full warranty on any 8xxx or 9xxx series nvidia cards because you can't tell if you'll get a bad one or not.
