Avast 5 pro (paid for version rates as excellent in latest testing).....Avast 5 free uses the same engines and virus definitions as the pro version but is free. You do get a little more functionality (sand-boxing and spam filtering, etc) in the pro but the level of active anti-virus protection is the same.

I used to use paid for Norton 2005 god what a piece of #$#$%#$, McAfee suite is good in my opinion. Fsecure is ok, BUT......some of the best are also free.

My choice Avast 5 free with Zone Alarm free firewall for Win7 x64, and a lot of awareness while surfing. Nothing and I mean Nothing beats an informed / proactive user and backups just in case....you know.I have run Avast free for 3 years now on 8 computers and while I occasionally see a virus warning I have not been infected. Chock one up the the educated consumer.

It really comes down to your risk tolerance.....if you feel better with paid then go that route....you may not be any better protected but you will sleep better, OR like me I sleep fine with my Avast 5 free, Zone alarm free firewall, and Windows Home Server backups for bare metal restore ability.

Windows Home Server now $69