I'm making lots of use of the MIDI track functionality.  I find myself wanting to take an audio segment, convert it to sample, and then use it on a midi track.  I don't believe there is a way to do this without the aide of an external sampler program.

My dream feature?  Click on segment, select "convert to sample" and a new midi track appears linked to a plugin sampler, ready to play.  

-

Devin