MacOS X. I'm a believer. First Unix that manages
to avoid looking like Unix
(except if you want it to). I've never seen an X windows manager that did
any good other than making the Unix metaphor just pretty, not less complicated.
OS X, on the other hand, does an excellent job at hiding it away from the
casual user, but not making it ridiculously difficult for people to get
their hands dirty if they want.
You forgot A/UX.
--
Eric Dittman
dittman(a)dittman.net