Boards
Songs where different versions can provoke totally different emotions.
Some good examples in my mind are Motion Picture Soundtrack by Radiohead (the early acoustic version vs. the album version), Nude by the same band (the earlier live ones with the jazz and organ etc. from the Kid A and HTTT tours are brilliant, and similar to the album version on In Rainbows but yet so different), and Here by Pavement (the soft album version vs. the Alternate Mix and Live version.)