Thanks for the recommendation of Squeezebox. I was nervous to see that Logitech bought them, thinking they'd be relegated to dumbed-down consumer level. Instead, I'll make them the start of my search.

Good idea of using the iPhone as a Wifi remote. Unfortunately, I'll be looking for that feature for the Droid. I imagine it will be weird paring an iMac media center with a Droid remote, considering Apple and Google don't get along so well.

Playing web radio is an important requirement. A goal is to replace terrestrial radio with web streams of terrestrial radio, but I imagine it will be tough to use a network music player to navigate to that content. Perhaps there's "wireless audio", where a main computer could receive the stream and broadcast it to household receivers. FM Transmitter hasn't worked, A2DP Bluetooth might not have the range, so I'm left wondering.

Thanks for the input.