This deal has ended.
Buy.com has Norton Internet Security 2008 Premier Edition for $19.99 after $20 and $40 mail-in rebates (the $40 rebate is good for a $40 prepaid Visa card), valid through 5/10. This is a substantial discount off the $80 retail price. This program is the gold standard in protecting your PC against viruses and spyware. Delivery is free with no sales tax (except CA, MA, MD, TN), and new Google Checkout users can get an additional $10 discount.