I've also encountered many systems trashed from the web because windows users routinely run with less tight security than they should because if they don't loads of "enriched experience" sites won't work.

Yeah. "Enriched" sites suck. I was updating somebody else's computer the other day because their free demo of Norton was expiring. I installed a new AV app for them, and then went out to download Zone Alarm (because Norton was their firewall, too), and Zone Alarm offered to scan me for spyware. Sure, I thought. That's great. Except that "feature" wanted me to install Active X! Ack! In the name of making my computer more secure, they wanted me to install the world's biggest security hole??? No thanks!