After having tried several anti-virus/anti-spyware tools over the years (and Norton was worst), I discovered AVG a few years ago.
I initially just used the free version, to see how I liked it. When I decided that I would use it on my other computers, I realized that they only allowed one free version per household. I had three computers to protect at that time and went with the paid version.
I haven't looked back since. I even paid for a two year license for one nephew at Thanksgiving when his laptop was infected.
Since then, they've gone to the suites thing. But you can disable what you don't want to use. It's still been one of the best for stability and minimal footprint.
Cheers,
Ancient Lady