Doug, infrastructure weaknesses like the DNS cache poisoning exploit mean that even if you only ever visit
www.west-wind.com or windowsupdate.microsoft.com, you may be diverted to a hacker site that takes advantage of an unpublished exploit (or invites you to accept the latest autoupdate activeX) to infect your machine.
IMHO AV is like a seatbelt: I hope I never need it, but I always wear it.
"... 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
