While we're talking about Copland and ELP:
Aaron Copland's Hoedown from his Appalachian Spring suite. (Americans may recognize it as the "Beef: What's for Dinner" commercial theme.)
The redo from Emerson, Lake & Palmer.
This is a tough call for me, because I absolutely love ELP's high-octane version. But I have to give the nod to Copland's orchestration, because I think the violins and pace fit the theme better, and I can't get over the feeling that when ELP did it, it was a showoff piece for Keith Emerson: "Oh, you think you're good? Well, listen to this."