We have a magazine in UK called PCPlus dont know if its published anywhere else, They done a huge article on AV's whereby they infected a computer with 500 well know virisus, tried 10 well known AV's. Here are the results:

1. PC -cillin 495/500 virisus recognized
2 Norton 454/500
3.Command AV 442/500
4.Sophos 440/500
5.McAfee 432/500
6.AVG (free edition) 398/500
7.EZ AV 387/500
8.Panda AV Platinum 340/500
9BitDefender (Home) 302/500
10.Achilles'sheid 254/500

This was done the back end of last year, so new versions of all the AV's have prob come out by now, but it gives a good idea of what AV to pick i think! I certinaly woul'nt recommend any of the bottom 4!