Moral of story: Backing up hard drive is good.
Amen. Another moral you are missing: Store your iTunes library separately on an external hard drive...NOT on your main boot drive, especially if it is a significant size library. You will save wear on your boot drive if you listen frequently, it is more portable if you want to move it from computer to computer. One other thing I learned using my G5 (2.7ghz dual-core) as a server - though it makes for a blazing fast server, it is a terrible power-hog. I plugged a watt-meter into my computer system when we noticed our electric bills had gone way up and determined that if left on as a server it uses as much power as my refrigerator! That's a whole lot of power! I'm looking into swapping over to a MacMini or a laptop since I really don't need the speed of a g5 as a server.