Tecmo Super Bowl
This was for a long time the gold standard for triumphant music, and still stands near the top of that field. Ending music is supposed to be among the best on the soundtrack, of course; it's part of your reward for completing the game, so it SHOULD be awesome. So epic ending tracks will make frequent appearances on this list (though not as many as final battle tracks do.)
There's not much NES music on this list; after I'm done, with some help, I'm going to do a best of the NES list. Tecmo was a quirky little company, but it sure delivered the goods when it came to music. (And awesome sports games.) (But definitely NOT SNES RPGs.)