I haven't seen a floppy based virus for five years. Everything is email and network now, and some are very sneaky. Many will infect just by appearing in the Outlook email preview window. They can even be implated by visiting a hostile Web site.
Expecting normal Windows users to not get infected is futile. I seldom see a computer that doesn't have at least a few infected files on it these days. Some antivirus program is needed.
I agree that Norton is the worst of the lot. Any product that's "Norton" anything, I avoid like the plague. They are all designed to be "smarter than the user", and put their hooks deep into the operating system. If something actually does go wrong, they can be highly destructive.