Point this out to him:
Over 900,000 viruses, trojans, worms etc on windows OS's.
Just under 20 for all mac OS's. (And these we're all in Classic -not OSX)
That alone is a big time saver for the IT dept. in trying to fix your computer.
I wish it were that easy! I'm not being cynical but I've worked for two mac-hating companies where the IT group would rather eat their own cooked hair than spend one second on a mac because most of them have no clue how to troubleshoot/network/admin/lockdown unix/macs. Why? Because they are usually swamped already with what they DO know and don't have time to learn unix/osx just to support a minority of users. It is a very hard sell.