Windows as secure as OSX....

[Colin_Camper]

Every badly administered 'big' OS will be vulnerable.

I would be surprised if OSX has more vulnerabilities than windows. Being BSD, it is a lot more mature and the source, like Linux, is reviewed by peers.
With windows, since last years worms, most trouble now is caused by IE and malware web sites that can directly infect a PC AND leave a door open for worms like netsky.
It would be surprising if the Unixes suffered the same fate since the security model makes it much harder for browser s/w to escalate privaleges and do these things.
Still, its possible with a badly administered Unix - look how many hosting companies run mysql as root!

[Colin_Camper]

Absolutely!

They have addressed some of the issues with default services in XPsp1 but the security model is still weak.
This means that if you are running a browser in NT+ (especially IE) you are gambling with your security.
At home, I'm behind a firewall/router, patched to the hilt, run stinger/adaware every week and only use IE on crappy ASP or M$Java sites.

As for the windows runs on DOS folk - try telling that to the ex digital VMS dudes who developed NT. The last DOS/Windows combi was the dreadful millenium - now who runs that?