I'd choose Unix over Windows any day. Specifically OpenSuSe as it's my favourite distro.
Point b is a bit silly since OSX has a decent interface too, and is pretty user friendly.
Windows, obviously.
HAHAHA thats BS about security. It's been proven countless times that macs CAN get viruses.
Thing is - no one pays attention to macs... who on earth would go for macs when windows has an ~85% marketshare?

