this info is so true, but also another reason why linux doesn't really get virus', is because there aren't really many (if any) big companies who use linux, and many people who make virus' want to cause maximum damage... so if the only people they can target are a few random home users, whats the point, right?
and your right about the 'system administrator' and 'limited user' (now called 'standard user' in vista) in M$ although i do believe you can still get virus' even though you are using a limited account in Windoze because M$ seems 2 limit the user in all the wrong ways, so the limitations don't prevent virus' which pretty much makes the admin account(s) and limited account(s) pretty much as useless as each other. Also there is no real account in M$ where you have 'all power' which is really stupid, but microsoft is sort of designed so any n00b can use it... i suppose that's why when people try linux for the first time they complain, or aren't quite sure what to do or how to do it...
that's my 4cents worth (round that off to 5cents
lol)