I can't understand why Apple can't shoehorn an iTunes server into an Airport Extreme or similar.
A Mac Mini running as a whole house media server is vastly overkill. A slightly beefed up AE with a Drobo hanging off the back, or even just 2TB Time Capsule would provide a true all in one media system from Apple.
One box sitting in the basement, or closet, quietly running the wireless network, acting as a backup target, but also providing streaming to Airport Expresses, ATVs, and iTunes clients around the house, it just seems like such an insanely obvious gap in the product line-up.
At even a hundred bucks over the price of the current Extreme, it'd still be way cheaper than a Mini, draw much less power, and be much less intimidating to non-techies. Particularly if existing iTunes setups could see the device, then offer the user the option to just auto push all content to it, and rejig themselves as streaming clients. One-click media server config for under $500 USD, seems like a deal to me.