It has to be said, the Apple Airport Express is a neato little gadget. Really does what it says on the tin, you plug the little gadget into a socket, hook up whatever speakers you like and have any Windows/Mac PC be on the same wireless network as it. It just magically 'appears' as an output destination in iTunes, load up a playlist and away it goes.

Only thing is, how are you going to have these mains powered devices (the Airport and some little powered speakers) safe in the bathroom? Hmm... you could put them in the celing above the bathroom and have proper celing speakers and an amp up there. With some deft fibre optic work you could get a remote control working too.

That would be awesome!

(edit) Oh sorry, this doesn't pass the 'multiple devices' rule. But it may make it up in coolness factor?