Fricken' amazing stuff. For a series that generally has incredible music, Castlevania: The Arcade has some of my absolute favorite versions of a lot of classic tunes.
Battle of the Heroes... you know, it's conducted by John Williams, and it's from Star Wars III: Revenge of the Sith. It plays when Anikin and Obi Wan face off after Anikin is recognized as the Sith Lord, Darth Vader. It's actually a very nice orchestrated piece...