When my company started up last year, we had only a few employees, and no IT group. So I ended up doing the IT work.
Now I really hate Windoze, I find it barely useable, and completely unstable. Unfortunately the others in my company were much more comfortable with Windoze, so their machines have XP installed.
Given that I was now going to have to Admin XP machines, I had a big concern over viruses/firewalls/etc. My biggest complaint against Windoze based virus software is how intrusive it is to the machine and the user. Also its difficult to administer most packages, and updating is a disaster on multiple machines.
So I called McAfee, and started complaining. I wrote a page of how lousy their software was, and everything that was bad with it. Guess what? All those popups, and constant interruptions are actually designed into the product to remind you that the product is there and working. They pointed out a different product line that they have, that doesn't have all of that crap. Well I gave it a try, fits like a dream.
The software auto updates (no user intervention), no popups, no constant reminders about what its doing, nothing. Just quiet protection. My users do nothing, everything is automatic, and I've never seen a popup.
The software is called "Mcafee Total Protection, for small business". I don't know if they will sell it to a normal user, but it is definitely what you want.