Well, as an IT geek at an ad agency, I can confirm that the TEEBTKAC and ID-Ten-T viruses are still abundant.
Hurry and get Spyware Sweeper and Norton Antivirus and for god’s sake, don’t click on anything that you see! Don’t read any e-mail – ever! Don’t feel relaxed while surfing the web, because identity thieves have put a key-logger in your registry and you’re … you’re …
Oh, waitaminnit. You bought a Mac. Never mind. Go. Enjoy. 
Virex came bundled with my Emac when I bought it 2 years ago. You may have this already installed.
I really like my dotmac account for several reasons: I can access all of my bookmarks and my address book from any computer, anywhere. I have my Quicken and music library backed up in iDisk in case anything happens to my computer. All native software updates are checked for and downloaded as soon as they become available. I recommend it highly.