I think all this talk about windows boxes being instantly swamped with insidious programmes within seconds of plugging in the ethernet is just bluster.
Apparently it depends on the ISP. Some of them block certain things, others give out free trials for av/firewall software...
I think it would be excellent if MOS or OS4 were made to run on some cheap PPC Macs. That is the only situation under which I would be interested in using any of them, either MOS, OS4, or a Mac.