Apparently, some people ended up with a copy of Portal 2 that had the original vocal version of Want you Gone instead of the autotuned version. A friend sent me a copy, however, the quality of it is TERRIBLE. You can still hear the vocals though.

If anybody knows how to get audio sounding clearer, please tell me!

http://clyp.it/ykof3eta.mp3

Located here: http://bit.ly/1lsA6BV

Related, if you trap yourself in Ricochet (the one for the overclocker achievement) by leaving both cubes in the upper room, it plays an unprocessed version of the voice line.