I got an email today about Avira antivirus as an existing customer - maybe this is interesting to some of you. If you are thinking of buying it and want 15% discount, send me your email and I will be able to "recommend a friend". (If you buy it then I get 90 days extension on my license). I run it on all my pcs at the moment.
For: In my view it's one of the more resource inextensive antivirus programs, it comes out consistently in the top end of antivirus tests for the several years. Inexpensive. Does its job.
Against: It is a bit hyperactive on "generic trojan" hits, although on the false positives tests it scores midtable, I rather have an antivirus that triggers more rather than not enough. Rather not have to run any antivirus

Anyways, let me know.
More info here.