Easy one for me, though - Monty Python's "Always Look On the Bright Side of Life". It only makes sense, to play the song from the end of "Life Of Brian", to mark the end of the life of Brian.
http://www.youtube.com/watch?v=WlBiLNN1NhQ
A good friend told me his wife wants "Baby Got Back" by Sir Mixalot played at her funeral - some inside joke. I love the irreverence of that idea.