> What's the point if you have to convert to mp3 before
> playback on the rio receiver?

Ideally the Rio client would support multiple formats (mp3, ogg, flac, etc.) natively. Where it cannot it should be able to play audio that's been transcoded by the server and support track switching on files of indeterminate length.

> How big are those files anyways (for an album?)

Roughly 3x the size of an MP3 encoded at 256kbps.

http://flac.sourceforge.net/comparison.html

Scroll down to see the compression ratios for the different lossless codecs.

--Reed (http://jreceiver.sourceforge.net)