I use a 12" iBook. Absolutely love it. I decided that the Powerbook wasn't quite worth the money for the extras you get with it. Also it's tougher than the Powerbook and since I cart mine around on tour I thought that was a good thing.
Get more memory, it never hurts. If you want Blue tooth, order it specifically because you can't add it internally once you've got it home. (other wise you just add a dongle thingy). Get Airport Express WiFi added too. (Very simple fit)
Open Source do great software and it's free.
The mac OS is very simple to use. Instead of right clicking, you'll find those functions along the top of the screen. David Pogue (O'Reilly press) has written a couple of very good books that I found invaluable. It doesn't take long to get used to and if you can use Windoze then you'll find the OS X easy to use. It's not hard at all.
I haven't had to run a PC emulator yet.
My next desk top will be a G5 Imac for sure.