My favorites:
Beethoven - 3rd part of Moonlight Sonata
Chopin - Revolutionary Etude
More:
Camille Saint-Saens - Danse Macabre
Edvard Grieg - In The Hall of the Mountain King (from Peter Gynt)
Modeste Moussorgsky - Night on Bald Mountain
Gounod - Faust - Act2. 04 Le veau d'or est toujours debout (mephistopheles aria). I love the phrase "people die for metal", so poeticly devilish.
Alan Silvestri - Journey To Transylvania (from soundtrack)
Shinjuku Thief - Sacred Fury (avant-garde, but fairly easy to listen to)
Alfred Schnittke - Koncherto-Grosso #1 (28 minutes of avant-garde, not easy to listen to, but very beautiful)
Mahavishnu Orchestra - Birds of Fire (avant-garde jazz, but close to classical)
If you're playing the piano, here are two simple parts that are really fun to play march-style:
Michal Oginski - Polonez Rodina 3rd part
Fur Elise 3rd part
They don't sound like it on recordings, since nobody plays them like that (except me, I guess). I think the best thing about those 3rd parts is that you can play angry.
