Anti-Spyware and anti-virus are useless to me; all they do is slow me down. I don't use them and I have yet to have any problems. If someone has compromised my computer and I don't know about it, chances are overwhelming that your standard anti-spyware/virus would not have picked them up anyway.
Anyway, in my experience, they flag a lot of benign files as dangerous which could be the case. If you legitimately have malware on your computer, you should learn to take some steps to protect yourself through safe browsing and implementing the good ol' "Policy of Least Privilege."
First, is safe browsing. This is pretty obvious but, you know, you might be REALLY tempted to navigate to a site that is offering up naked pictures of Lindsay Lohands or Nancy Pelosi or whoever it is that tickles your fancy, but those kinds of sites often use "unscrupulous business practices" and can open you up to dangerous situations. Same goes for warez and P2P stuff.
The second is the Policy of Least Privilege. Don't be running highly vulnerable programs like Firefox/IE as root/Administrator. If you're compromised as root you're toast, but if you do all you Lindsey Lowham picture downloading as a lowly, unprivileged user and you get compromised there is not much they can do.
Anyway, like I said, this stuff seems like common sense, but I just figured I would mention it because it has kept the Bonzi buddy at bay for at least a little while.
Of course targeted attacks are a different story, however
If someone REALLY wants in any computer and they are good enough...they are getting in. Norton won't help you there.