Why spend money.?
Anti/virus, either Avast or AVG free edition.
Spyware, Adaware, Spybot A2, Spywareblaster, and a few others. Firewall, Zonelabs zonealarm.
These are some programs I have been using for numerous years now, and the last virus i was infected with was the original "Blaster", and only because at the time, I saw no need for an A/v.