Anyway.. I've used both the Seagate Barracuda 500GB as well as the Western Digital 500GB drives and the WD win hands down. My Seagate was loud (for a brand new drive) and died within months of installation. I RMA'd and the second died within 5 weeks! I had bought these drives from ebuyer, and with their amazing customer service allowed me to change the second RMA request so that I got a WD drive instead - Never had a problem since!
Infact, I now use three WD 500GB drives.
You can get a WD 500GB drive from ebuyer at around £50 ($76, €55)
Currently, If I were in the market for a drive, I would get either a WD Caviar Black or a Seagate 7200.12. The other WDs are good too, but I wouldn't get a Seagate 7200.11 (they've had a lot of problems with this line) or 7200.10 (loud, relatively slow - they are quite reliable, but older generation drives, and are no longer worth it)