The best two choices of mine are....
1. McAfee (Network Associate) that I use for my home computer...it's just great ever...I used to use NAV2004...it made my computer a lit slow but secure, when I change to McAfee..just run great and secure as well.
2. Trend Micro Software www.trendmicro.com, it's the best one for the corporate network (such Domain etc.), At my school we use this one, I don't think any others AntiVirus can beat it, but it just lack of Firewall.

by the way, all antivirus in nowaday are still good, just keep update it...You will be fine.