because probably it's a top title like internet explorer and they've had time to make spyware that bypasses its internal security. Chrome is new, it'll be off that list in half a year.

Opera makes the list because it's not important enough to write software for.

Eh, I use Firefox, have used it on my PC for two years, and I never had an anti-virus or a Firewall other than the standard Vista thingy.

I downloaded AVG Free yesterday and scanned for everything, had no infected files at all.

Anti-virii and Firewalls are mostly for important people, risktakers and idiots. If you're not important, and you're smart enough to stay away from dangerous sites, nothing's gonna happen.