Following great advice here - I was using MOG for a while. Good quality stream, works on my old Squeezebox SB3 and mobile.... but the android app is appalling, and development has ceased.
I used Rhapsody for a bit - major improvement on the android interface and, as a major plus, allows you to store local content on your external SD card. Also works on my old SB3. One downside is that if I use it on more than one device it's $15 a month. I think the quality is ok.
Spotify doesn't work on my old SB3 (that I have hooked up to a stereo system for the living area) and does not allow changing offline storage location... and I'm not sure the streaming quality has been too great compared to MOG, but I wouldn't throw myself onto a sword over that opinion without detailed ABX.
Are there any other options along these lines that might work? Seems rhapsody is about the best for this combination of Android / SB3 compatibility but there's been so many new services I wanted to check with fellow audio geeks here first.