So it's really easy to set up and easy to use, once you get used to the oddities (command Q...). It's basically a BSD, so you get Bash and Python and gcc and Vim etc.
However, I'm starting to discover while it is Unix, it's got its problems. On Ubuntu, everything is just an apt-get away. I can check out bug reports on launchpad and get unstable fixes, and not have to wait for an update from the Apple gods. On OSX, you need to use fink or darwinports, which isn't integrated with the OS (anyone said Apple gcc vs fink gcc?). Apple just likes doing things its own way, like rewriting config files for you (even though you edited them manually), having obscure config options (.MacOSX/environment.plist???).
So as much as I enjoy the interface, I think my next machine will be some sort of Thinkpad + Ubuntu, for all that brown themed ugliness :)
(oh, and I swear the white macbook scratches and scuffs the second you take it out of the box, get a black one or a pro.)