I recommend Symantec Corporate edition for virus protection. Doesn't clog up your computer like all the Norton packages do. Oh, and btw, it's free updates w/o a cd-key. You're not verifying anything, no work-arounds for those KaZaA downloaded version, nothing!
Spybot, Symatec Corporate Virus Protection, and *name of really good spyware detector that even found articles about anarchy too goes here* are my recommendations.