Avast anti virus is great. Downloaded it recently since my Norton subscription is ending. It does not hog system resources like Norton and the price is great!
Free for home non commercial use. http://www.avast.com/
I use Symantec Antivirus Corporate Edition from over a year and I'm not dissapointed. NOD 32 and Avast are good, but from my experience, I recommend Symantec (maybe others won't agree my point of view, but that's my opinion).