Use common sense; stay away from the binaries, porn, et al nasties, use AVG,
Ad-Aware, Spy-bot, and surf on. (shut off the java scripts and crunch those
cookies....regularly).
IMHO, the easiest way to keep your private PC safe is to run it behind a
hardware DSL router. For additional security use ClamWin (free, easy and
fast to update). Use Firefox for surfing instead of MSIE.