There's a thread like this about Game Boy soundtracks, but we all know how much better the NES sounds than that old thing 
Now, I want you guys to dig deep and find some really obscure and wonderful stuff. Maybe games that have fallen through the cracks, or maybe an often ignored track from a more popular game. Just post some good shit. To kick things off, here's the Top 30 soundtracks as picked by The Shizz, which I'd say is more or less pretty definitive: http://good-evil.net/_/features/top-30-nes-soundtracks
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And now, some of my picks:
Akagawa Jirou no Yuurei Ressha
I very recently decided to play every NES/Famicom game in alphabetical order for fun. (You can tell by the title of this game I'm still just in the A's haha) I came across this Japanese text adventure game I couldn't read at all (it does have some pretty decent full screen art for a text adventure though), but I thought the music was great. It's simple, and most of the time only uses the pulse and triangle channels (a style I'm actually a fan of), but the tracks are very well put together and catchy.
Ys - Ancient Ys Vanished Omen
A Japanese RPG with some great tracks. I strongly recommend listening to the title screen track; it's wonderfully calming and emotional (song 12 of the nsf)
Tetris 2 + Bombliss
Bombliss is an amazing Tetris-like game that came with the Japanese Tetris 2 - go play it. Recommended listening: song 11 of the nsf. I could (and have) listened to this loop for hours.
Sweet Home - Fresco Theme
My favorite track from the Sweet Home soundtrack. While playing, this song is like a calming oasis in a huge spooky mansion.
Lastly, I'm sure 99% of you know how kickass the Gimmick soundtrack is, but I can't talk about NES music without bringing it up, so here's my favorite track. A pinnacle of chipmusic, for sure. Oh, and sorry all the games I picked are Famicom games, it wasn't intentional!
