This deal has ended.
Buy.com has Norton SystemWorks 2008 Standard Edition for $12.99 after $20 and $30 mail-in rebates, valid through 5/31. This is a substantial discount off the $70 retail price. This program is the gold standard in protecting your PC against viruses and spyware (and is Microsoft Vista compatible). Delivery is free with no sales tax (except CA, MA, MD, TN), and new Google Checkout users can get an additional $10 discount.