This deal has ended.
Buy.com has the Fantom Titanium 500gb External Hard Drive for only $129.95 after a $20 mail-in rebate valid through 3/27. Plus, shipping is free and there is no sales tax (except CA, MA, MD, TN). Under $0.26 per gigabyte is the best deal I've ever seen for external storage. Also of note: Buy.com has a new and very-rare $5 off $50 coupon valid in all stores for new customers through 3/31; new Google Checkout users can get a $10 off discount for signing up (you can't get both).