I've never used audiogalaxy, give it a go and see how it compares. Its the fastest software setup imaginable so relatively little investment to get it going.
Since I mentioned this thread in the Keeping retail media thread I figured I'd update it.
I'm still happily using subsonic, except I modded it with Music Cabinet. This is a free mod that sits ontop of the work done by subsonic and basically adds a whole lot more awesome to the whole experience. I particularly use the Artist Radio a lot when there's a type of music I want to listen to.
If you're using subsonic now then definately check out music cabinet as well.