The problem of streaming audio from one computer to another has cropped up a few times over the years in different forms. I had to solve this again recently, but this time around I really like the solution.
I use two computers in my apartment. My black MacBook is attached to a 24″ Dell monitor in the bedroom. I also have a 2006 Mac mini plugged into my projector and home theater in the living room. My Drobo is attached to the mini and holds my music collection. I do most of my work on the machine in the bedroom and use iTunes to mount the library over the network. If I want to listen to music in the living room, I close iTunes and then connect to the mini using VNC and reopen it. This lets me maintain a consistent library and manage my music from whatever machine I’m using.