You're right there, Xaq.
I only had one Virus on OS 8 and 9. It was called "666" (AKA SevenDust) and fortunately it was the undestructive version. Some versions of 666 would destroy data right and left or just infect menu resources. I just got an annoying version that did nothing harmful. But I killed it with a free Virus scanner called Agax and that was that.
Other than that, I've only seen viruses on PC's. My first was AntiBIOS on an infected floppy disk at school. Killed it instantly. My favorite was Class.poppy which wreaked havok at work. Was fun to look at the source code, though. (It's a VBA Virus)
But there's ONE virus that I like. It isn't one I had. It's one my friend had on his XP PC two months ago. It destroyed half his daya in a few minutes before he stopped it. And it emailed itself to his friends via his addressbook and caused them all to get mad at him. needless to say, his iMac arrives shortly.
To quote my friend: "Windows is the worst operating system ever made!"