The problem of iPod and iTunes only working together has been highlighted again, this time by legal action taken against Apple by an iTunes user. From the BBC:

A user of Apple's iTunes music service is suing the firm saying it is unfair he can only use an iPod to play songs.
He says Apple is breaking anti-competition laws in refusing to let other music players work with the site.

Apple, which opened its online store in 2003 after launching the iPod in 2001, uses technology to ensure each song bought only plays on the iPod.

Californian Thomas Slattery filed the suit in the US District Court in San Jose and is seeking damages.

"Apple has turned an open and interactive standard into an artifice that prevents consumers from using the portable hard drive digital music player of their choice," the lawsuit states.

From a legal point of view, I don't think it's a good one to bet on. Choice does exist in the market, just not on the Apple side. The Windows Media platform for example, he can use a range of stores like Napster, MSN Music and a range of devices, the Zen Micro and Rio Carbon for example, both of which to be frank are better then an iPod anyway. Of course this is no good for the music he has already purchased which is effectively useless. Something I've been warning people about for longer then I care to remember.

The user has plenty of choice - just avoid Apple.