For the last month I have been using AVG Free instead of Norton Anti-Virus. I'm no longer paying $25/year for updates when there's software giving the same thing for nothing, and without bogging down the machine as much. So far so good. AVG scans my machine with a low priority process that seems to just stay out of the way.
Best of all, I no longer have any dollar costs for maintaining my computer, which makes it easier to consider switching to Mac.
I've used some version of Norton Utilities or other for over twenty years. The original Norton Utilities were really powerful command-line tools, including a fabulous disk sector editor for DOS which I used for endless investigation and mutation of floppy disks. It was a nice little tool for really understanding disk structure, recovering lost data and, every once in a while, unlocking nifty little secrets. Playing with computers just isn't the same without a powerful Norton utility.