Hey thanks for the reply!
The main reasons I was looking for the Cube are (in order of importance):
1) I live in Japan (space is at a premium!!)
2) Headless (don't need a monitor, VNC!! kinda fits in with #1)
3) Quiet (my wife always complains about my PM G5, and it's freaking QUIET!)
4) Gigabit Ethernet (my current iMac G3 isn't upgradeable, the B&W G3 comes with 10/100, but I can upgrade that with a PCI card)
I'm not too concerned about expandability. If I need more HD space, I can always hookup an external FW400 HD. That would be plenty. It would basically be just for web/mail/file/music serving so it's not going to be taxed too much. It's all personal stuff, no business, so it's not going to get much over a few 100MB (not including my iTunes collection which is already 35GB)
[EDIT]I'd like to stick with OS X for ease of use. I used to have a 1.1GHz Celeron Linux machine running as my server, but it was a pain in the butt to administrate. With all the cool tools available for OS X, it just makes it easier. I work for IT, dealing with Winbloz problems all day long... I want to come home to something that's easy... and works