I'm a big fan of Crestron, but I don't think that for basic audio distribution you get the best value out of it. Reliability is second to none, but the price is a bit high unless you already have some need for it. They do have Adagio zone amplifiers which are competitvely priced...
Yet, if you simply want basic distributed audio, there are a half dozen less expensive solutions which will still work very well. I have heard good things about Sonos as well.
For a fully integrated home, or a complex home theater, if you already were putting Crestron in, then the addition of multiple sources (XM, FM, iPod, etc.) throughout your home could be well worth it, and any company worth a darn is going to have some pretty stock programming which won't run to crazy a number, but should work well.