Haha, I was asking myself all the same questions when mine arrived ! Despite the bad buying experience I had, I couldn't be happier with the machine. Seriously (I've been using XP all my life), I can't ever buy a PC again. The OS X is jsut that good. It's better than XP, but WAY better than Vista. If you try Vista after using OS X for 2 weeks, youll see what I mean. We got a vista computer in our house, and it was such a mess setting it up. I couldn't believe how much bloatware they fill it with. I also couldn't believe how stupid the menus are set up (i.e. Add remove programs changed to "Program Features"! Why fix it if it ain't broken!). And the "see thru" window thing is useless, and if you have more than like 3 windows open, flip 3d is useless. Honestly, I thought with my Mac I'd have to boot into windows at least once per week. I haven't even felt the need to install it! You''ll truly understand what all the hype is about! It's really that great.
\rant
Enjoy your machine! Dont forget to try out all the apple apps...try Mail...it's really nice, simple, and works better than Outlook (it's more stable). Check out spotlight, too. FOr messaging, I switched to Adium (it works with your MSN account). The GUI is better, and the messages are tabbed. You'll find the dashboard useful, and don't forget theres many more widgets at apple.com.