Andi – is this music for teaching group exercise, or for personal workouts?
Most of my music for teaching group ex comes from sources like Power Music, YesFitness Music, Muscle Mixes, Dynamix, and Move-Ya (a European company). Some of these companies also have music for personal workouts.
For classes where I don’t need perfectly 32-count phrased selections, I sometimes download from Itunes and Amazon.
There is also a Music Board on http://www.turnstep.com where you can ask for input from instructors around the world.
I’m looking forward to seeing how others respond to your question!