Auto-edit

Auto-tune is pretty cool. You give it a list of acceptable pitches (ie: the key of the song). It then does a pitch analysis of your (usually vocal) track and pitch shifts every note to the nearest acceptable pitch.

The pitch shifting is quite subtle, but you can still hear it (it sounds sort of phaser-y). Moreover, the pitch shift removes character from the original track.

Better would be if you could record several takes of the track (as is usually done anyway). Auto-edit would then dynamically cut between takes, always choosing the one that is most in tune. The result is an in-tune track without any pitch shifting distortion.

While your at it, the algorithm could be given other criteria for auto- editing, for example giving negative weight to pops (sometimes happens when you say b's or p's). It could also take parameters for when it's allowed to cut (moments of silence, for example).

You could essentially use the algorithm that scores your vocals in Rock Band (video game).