Luke would be into choral chamber music. Han would listen to Audioslave. Leia would be into.. oh I dunno.. Lyle Lovett. or something. and Vader would listen to opera.
Padme would be into 'bubble-gum-rock' and/or hip-hop so that basically means a new band every week. the pop music "flavor of the month" club.
the droids, of course, techno.
tarkin, willie nelson.
grievous, death metal.
and obiwan would be trippin to Pink Floyd.