For my money (or lack of) I'd have to say Avast. It was totally free - updates itself on a regular basis - and also scans the computers memory for viruses. Before I had heard about it - my system was running sooooooo painfully slow I didn't know why. Avast found a Win32 polip virus that both Norton and McAfee DID NOT SEE.!

Here's two catches (at least for me) - While it has customizeable levels of scanning depth - it is pretty slow. I have 200+ gigs of hard drive space so I usually set it an forget it over night.

The other catch is the memory scan which really should be set to be done BEFORE Windows fully boots (something you can set the program to do easily) but it requires you to have PS/2 keyboard an mouse connections (it won't work with USB)

I run the active scanning all the time (even when i'm rendering in poser or d/s) - it makes little difference on render times.

And one final word on Anti-Viruses: Before you install a new one - make sure the old one is fully gone. Nothing mucks up a system faster (from experience here) then having bits of an old AV program hanging around when you're trying to install/run a new one.

Hope this helps. :)

Just enjoying the Vue. :0)