Kirk,
I am using an Airport Express in the bedroom with analog out to a pair of remote-controlled Kanto powered speakers, and it sounds OK.
If I were going into an amp or receiver that had a better integrated DAC (how good can the DAC be in a $99 Airport Express?), I would probably want to try the Toslink output.
One of the few third-party Airport Express remotes I've seen, the Tripp Lite URM-17A (
http://www.newegg.com/Product/Product.aspx?Item=N82E16880109001&Tpk=airport%20express%20remote) doesn't support Vista 64 (!) which is what I have, but would work with the MAC Mini and give
full iTunes control.
So, in my case, I'm glad I have remote controlled speakers, but if I had a MAC setup or a 32bit Windows and wanted the simplicity of powered speakers, I would get one of those remotes and my speaker choice would most likely be a pair of the Audioengine A5 powered speakers at an MSRP of $350. They also have a version in
solid bamboo enclosures (A5N) for $100 more.
Steve