TigerDirect offers the HP p2050x 500GB USB 2.0 Portable External Hard Drive in Black, model no. HPHHD2E30500AX1-RBU, bundled with Total Defense Premium Internet Security Software for $84.99. These $15 and $60 mail-in rebates cut it to $9.99. With around $4 for shipping, that's $0.03/GB and the second-lowest total price we've seen for any 500GB hard drive. (It's also a current price low for this bundle by $102.) The portable hard drive is Mac- and Windows-compatible. Deal ends December 31.

Note: Total Defense Premium Internet Security must be activated before the rebate can be redeemed, which involves providing your credit card information. However, you can cancel the service at any time within the first year without incurring any additional charges.