I don't sing so much when I'm riding as much as I have songs stuck in my head. People who know me well know that there's rarely a time when I don't have one song or another playing in my head. A few songs that would appear on my bicycling soundtrack would be "Who Made Who" by ACDC and "Satisfaction" by the Stones. From time to time I'll look back over my shoulder on the road and see a large semi gearing up behind me and the Terminator 2 soundtrack will go off in my head.
As far as music in the shop goes, I once brought my Trek in to the shop because my fork was in some seriously messed up shape. The mechanic took my ride into the back. I was seriously worried. It was then that I heard the Blade Runner soundtrack by Vangelis on their stereo. Blade Runner is easily one of my top three favorite movies ever. I knew then that everything was going to be ok.
Other music while cycling includes anything from Pink Floyd: The Wall and any number of Tragically Hip tunes and of course Ride Of The Valkyries by Wagner.