Friend recently bought one in NYC. Works splendidly with his iMac over a Firewire connection. He reckons battery life is enough for a reasonable day's listening while walking, jogging, rowing machine etc. He's put most of his 200+ CD collection onto it.
However, he's now pissed orf as Apple have just released a new line that are cuter, slimmer and have more storage. They also have docking stations to allow you to set it up next to your hi-fi and listen through that. This is in line with Apple's new focus on music (iTunes Music Store etc.) - visit
http://www.applemusic.com for info.