Seen some pretty great examples of music played loudly over the PA as bands have come onstage over the years.
One that springs to mind immediately would be Blur in the Parklife tour era coming on to Get A Bloomin Move On (Self Preservation Society) from the soundtrack to The Italian Job. Definitely captured the mood of the early Britpop era.

Any other good ones you have seen?
Or if you're IN a band and you've had a choice what to walk onto, what did you pick?