Well, maybe two different shows since my selections don't really go together, but anyway..
Phantom of the Opera. Actually a 1A band did a Phantom of the Opera show at state this year, but unfortunatly, us 4A's didn't get there till the day after.
Armenian Dances: Part II by Alfred Reed. Maybe not the most sensible piece to march to, but its got such energy that I would love to just be able to play it for so many people so that they could hear it.