avast home edition (free) http://www.avast.com

Avast Home is one of the best AV programs available, and it's free.

I agree.

I use firefox to prevent spyware, but this has caught a trojan inside a rar file while it was downloading, I love it, not to mention it's not really resource heavy like Mcafee.

EDIT: Wow this post is a week or two old, I should really check these forums more often.

My firefox was taken over by something that kept opening pages on me. I had to uninstall it.