My all time favourites are the main theme from The legend of zelda and two songs from the megaman serie: Willy's stage theme from megaman 2 and the tomahawk man stage from mega man 6, but the megamans from NES in general had the best songs, even comparing them with today games :P.
-- Live only for tomorrow, and you will have a lot of empty yesterdays today--
Tavin: "Old school megaman is THE BEST megaman" courtesy of fkusumot :)
My mind has changed. My strength has not. Kamahl, Fist of Krosa