I've only very rarely heard music on BA, but actually I quite like it. It calms the mood of cabin during boarding / landing.

On LX, music is common. For most of the year, it is "background noise" and not very distinctive. But in the run up to Christmas, there is nothing better than landing in Zurich, with snow on the ground, with carols or Christmas songs playing. Although I don't think Chris Rea's "DRIVING home for Christmas" is particularly suitable, on many levels!