Currently I have Rhythmbox and Spotify(beta with apps) installed on my 12.04 system. I use Spotify a lot more than Rhythmbox, and I would therefore prefer (for ergonomical and aesthetic reasons) that Spotify was listed first. Is there a way I can do this without removing Rhythmbox?
(converted OP comment to answer)
While I was looking for a way to change the location where notifications show up, I stumbled upon a settings in dconf.
If you go to com, then canonical, then indicator, and then into sound you will find an option to change the order of the different entries in the Sound Menu.