Low-cost Roku SoundBridge M500 networks your music collection

Looking for a relatively inexpensive way to pipe tunes from your computer to the stereo in your living room, without resorting to running a ginormous cable? Enter Roku's SoundBridge line of network music players.

The SoundBridge line comes in 3 flavors: big, small, and smaller. The smallest of the line, the M500, was
announced today. The only major difference between the units is in their display size, so if you are just as happy with a 40-character LCD as with its hi-res big brother, you can save yourself several hundred clams by going with the M500.

The SoundBridge supports major music formats and is also compatible with Windows, making this device a good choice for mixed computing environments. For Mac-only environments, I'd be interested in seeing a comparison between the SoundBridge and the Airport Express for playing networked music – anybody have experience with either to share? I'm toying with the idea of setting up such a system, although part of me is a bit partial to my current system in which different music is playing in different rooms of the house. It's usually a fun surprise to see what's playing in the living room when I come downstairs from my office, and vice versa. I enjoy the randomness and the variety...