I have tried the following AV's;
Kaprasky For Windows 7 Beta - Didn't like it, kept asking me about every little thing.
Norton Anti-Virus Gamer Edition - Was fairly light-weight and worked well.
McAfee - Was decent, wasn't picking up much.
OneCare - Was using a lot of my resources and didn't pick up much.
Panda - Was a resource hog, extended my 'boot up' time about 2 minutes. Asked me about every little thing.
AVG - Was light-weight and picked up some things.
Morro - By far my favorite, light-weight, picks up things none of the following picked up on my system, and doesn't take forever to load.
Morro wins. =D