I just bought Nicecast for my home stereo.
One of my problems with my home theater system is sometimes I have something on -- news, sports, music -- that I want to listen to as I wander either to my office or to the new addition we're putting in the house.
I can, of course, use various whole-home audio solutions, and I use some of those: a wireless speaker that sits in the kitchen and can be carried elsewhere, and audio output to an amp for some outdoor speakers, and to an amp in the bedroom. But wires are not as easily strung to other locations, and most wireless solutions stink.
I already have computers in the additional locations I want to listen to this audio, and a computer in the base location, so: enter Nicecast. I have the same audio that goes to the other amps, and the wireless speaker, fed back to the main computer (which may include the audio that computer is producing), which is then streamed to the rest of the LAN.
Now I can be in the upstairs addition and listen to the baseball game that's on the TV downstairs. Or if I am listening to the news and I need to go to the bathroom and happen to have my laptop with me