avg and it's free

Avast> also a free one. Works great and it is real time even on websites. Stops stuff before it even gets into your machine.

Here is a direct link for it.
http://www.avast.com/eng/download-avast-home.html

Avira anti virus personal edition.

avast i find norton and mcafee to be resource hogs

Yes Avast uses very minimal system resources. It will also update by itslelf and you wouldnt even notice.

I used to use AVG but they let a few through the cracks. I also use spyware terminator as well but it's blocking a little more than it should right now and i can't get it to stop, even if i put it on the white list.

I use the DDS (Don't download shit) Antivirus Software.

I use AVG although have been considering switching to Avast (how is it?) i had norton for years and just got tired of the resources being drained, the constant LACK of virus protection and the fact that for 2 weeks before your Norton subsricption runs out you all of a sudden get 40 viruses a day....how convenient

Like I have posted before Avast works great. I wouldnt use anything else.

McAfee VirusScan Enterprise Edition 8.5i. SOOOO much better than that retail crap they put out.