500 GB HDD, Samsung SpinPoint F3 HD502HJ , Western Digital Blue WD5000AAKS $42.5 + FS

[ccengineer]

ewiz has

Samsung SpinPoint F3 HD502HJ 500GB SATA2 7200rpm 16MB Hard Drive

Seagate ST3500418AS 500GB SATA2 7200rpm 16MB Hard Drive

Western Digital Caviar Blue WD5000AAKS 500GB SATA2 7200rpm 16MB Hard Drive

Western Digital Caviar Green WD5000AADS 500GB SATA2 32MB Lower Power Hard Drive

For $50 + FS + 15% off your purchase w/ coupon MAGIC15 (Expires 5/23/10 or after first 2,000 uses) = $42.5 AC

They also have Western Digital Caviar Green WD6400AADS 640GB SATA2 32MB Hard Drive for $46.75 AC

You might be able to get BCB also.