This deal has ended.
Buy.com has the 500GB Fantom Drives G-Force USB 2.0 External Hard Drive priced at $99.99 after this $20 mail-in rebate (expires 6/30). Shipping is free and there is no sales tax (except CA, MA, MD, TN). It's compatible with either Mac or PC, it comes with a one-year warranty, and $0.19 per gigabyte is a great price on external storage. Plus, new Google Checkout users can get an additional $10 discount for signing up or first-time Buy.com customers can use this $5 off $100 coupon (you can't get both).