Congratulations! I made the switch back in April of this year with a dual 2GHz G5 and 20" cinematic display. I had been in California on business and stopped into the Apple store at the mall in San Jose, CA, and chatted with the guru at the Genius Bar there. Having not had an Apple since my IIGS, I was pleasantly surprised by all the Unix underpinnings of OS X (I'm also a Linux user, so this was GREAT news.) I ordered my setup about a month after returning home.
Funny story: I had my new system set up and running all of 30 minutes, and began demonstrating it to my wife. After about 5 minutes on it, she tells me, "I want one, too!" Well, we didn't get another G5, but her PIII-550 box that used to run Windows was shortly replaced by a nice little iMac.
We're now a couple of Apple users and will NEVER look back!