Hey,
Don't go near that thing for music.
1. There are no PCI slots. 98% of all audio cards sit in the PCI slot. If you get this machine, you will be stuck with its crappy integrated card, or else you will be stuck with getting a USB or Firewire card, which frankly don't always do exactly what they claim.
2. There is no AGP slot, which means you cannot choose your video card. A lot of pros (and even us lowly amateurs) like to use dual monitors in their setups, this requires that you install a 3rd party card like from ATI or Matrox. It does have a video-out port, maybe you can connect another monitor this way?
3. You can only put in 1gb RAM; you can install 2gb in a desktop.
4. You can only put in a 750mhz processor in the eMac; you can run dual 1.42ghz chips in a desktop.
The eMac is basically a toy for kids at school to play with, don't waste your time on it.
If you're SERIOUS enough to want to fork out this much money on a computer for audio, get a real computer!
Take care,
Nick