I can tell you Norton AntiVirus is a piece of junk. It will quarantine, some of its own key files claiming there's a virus in them, when in fact they are clean, and then give you a message that you need to uninstall and reinstall the program, and end up deleting the clean files, when you uninstall and reinstall Norton AntiVirus. On top of this, when I tried it, decided it wasn't going to stay synced up with the Liveupdate server, even after having downloaded the latest updates. I had this happen to me, after trying it awhile back.
I won't use NOD32, it generated a false positive for spyware in the download manager for a music download service I subscribe to, and in fact there is no spyware in said download manager.
I actually got Windows Live OneCare 2.0 working decent on my computer, finally. It uses less resources than a lot of other internet security packages I have tried in the past.