Remember Rdio? I do. A beautiful music streaming service that was eventually outmuscled by Spotify, Google Play Music and the like. If you miss its light, well-considered design like I do, you might be interested in "Spotio," a new Spotify theme by designer and writer Devin Halladay. The legality of his work is a tad questionable, but until it's pulled by Spotify's overlords you can grab it right here. You'll need to set your Mac's security preferences to accept apps from "anywhere," and close the regular version from Spotify HQ. Then it's just a matter of deleting the original app from your Mac, should you prefer Halladay's Rdio-inspired alternative.
It's only a reskin, so temper your expectations -- this isn't a full recreation of the Rdio interface. Still, for fans of the now deceased music streaming service, it's a nice way to show your appreciation. We miss you, Rdio.