My favourite used to be Dean Martin singing 'Dreamer with a penny' going into 'It came from Japan' by the Von Bondies. Nicely jarring, but a little bit showy.
But this morning all that changed. 'Crystal Japan' by David Bowie into 'There goes my outfit' by The Dears. A seamless shift in mood, it took me by suprise listening to the computer pick random tracks.
What is your prized, knockout one-two mixtape combo?