
I am a "Technologist", a Technology enthusiast that is usually the one that is called should a major catastrophe strike an end user. My saga of computer rescues becomes a plot that is ever so thickening, if not only for the fact that's it's becoming incredibly easy for hackers and malicious code writers these days to invade personal property to find, seek, and destroy. Each year, virus and hacker threats increase, and in addition the damage trail left behind is something of a problem. Not to forget, a majority of "PC Panic" cases I've come across are often times the same common, "major" problem.
I don't use a firewall (have a hardware firewall, but it's turned off), and I don't have anti-virus software running in the background.
I do occasional checks every now and then for the not-so-obvious ones (and no, my antivir isn't damaged by a virus. It gets reinstalled during every update).
And I never revieved a single virus/worm in my life.
I think that when you are an experienced user, you shouldn't need either one (firewall nor AV). I think it's more imperative for the non-experts and companies.