Erik rightly complains about the lack of a does-it-all AirPort base station from Apple.
Inexplicably, the AirPort Extreme and Time Capsule don’t offer AirTunes. This might make you think AirTunes as an idea has been quietly canned, but Apple recently added it to the Apple TV.
The AirPort Express isn’t 802.11n yet.
The Apple TV offers no bridging. Speaking of which, neither does a regular Mac OS X client. Windows XP Professional, on the other hand, did this just fine six years ago.
Given that AirTunes (not astonishingly) requires some form of audio-out port (ideally an analog and digital one, like on the AirPort Express), this isn’t a feature that could be added in software to the AirPort Extreme, nor to the Time Capsule. Why, though, has this not been added long ago, such as part of the switch to 802.11n and new design, over a year ago?
Similarly, adding 802.11n to the AirPort Express requires different hardware — fair enough.
But!
Allow the AppleTV to bridge via its ethernet port. [..] This should just be a software thing, right?
Exactly. Much like they’ve added AirTunes, they should add bridging.
Of course, just as I’m about to post this, Jesper has already put it more succinctly.