"Don't Stop Me Now" - works great just before going out and when you're already drunk
And my friends' favourite (when they were a couple) was "You Don't Fool Me". They're not Queen fans, but they just love this one.
I use to do the lights for my friend who was a DJ in a Brooklyn Disco (of all places) and Don't Try Suicide was hot, especially afer a few 7 and 7s.
People on the dance floor went crazy even though it wasn't a dance song.