Norton was a pita. We then cycled through several options that all developed a tendency to hog resource or sit chugging away infuriatingly when you just want to wake your machine from sleep. Norton does not hog resource any more and is well worth a try IMHO- though if you have some other standard that works for you and is up there in the virus detection stats, then I agree you're best to stick with the devil you know.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1