@ozexec,
I've tried 3 different types of antivirus on the computers I've owned in my life.
McAfee, Symantec Norton, and one of the open source. I can't remember which one. I had it awhile back when I couldn't afford to keep subscribing to either of the two biggies listed above. Didn't keep it because it was terribly slow and it wasn't user friendly for those without an administrative/IT background.
In this computer, I have Norton 2008 I believe. When I finally land a job I plan to upgrade to the latest edition, Norton 2010 because its getting monstrously rave reviews (system speed wise, etc....)