The Dink Network

The Fierce Battle- Nobuo Uematsu

This is, in my opinion, better than his more modern Battle Conditions and is the best boss fight music ever, in my opinion. It's from Final Fantasy III (FF IV in Japan) and is a game that has the best storyline of them all. Can you top this?

Why? Because it's crams so much emotion into the song and suits the situation so perfectly. Too bad the boss himself is such a kitty.

EDIT: @Kris, III was VI in Japan. II was IV in Japan.

Whoops, my bad.

But, yeah. Listening to it now, it is a very respectable boss theme, but there is another boss theme that trumps it, World Revolution- Yasunori Matsuda

This theme shifts between Crono's theme and Lavos' theme in an epic way.

That's good boss music, but I wouldn't say the best ever Even in FFVI I would say the final boss song or even the regular boss songs are better imo
And the Riku boss song is awesome yes

For me, the best boss battle music ever would be a tie between Promised Pain from Xenosaga Episode III and Dancing with Domz from Beyond Good & Evil and Dark Impetus from Kingdom Hearts Birth By Sleep.

There's probably more that I can't come up with right now

There is also Shadowlord from the game Nier. If you know the storyline behind the game this song is both epic and saddening. A remix of the song was made by someone on YT called ShiroiYuriNoOtomi. Better than the original in my opinion and a hell of a lot better than the Whitenote Remix (Which came in the official DLC).
(Okay, I'm breaking my own rules by adding this as well since this isn't boss fight music, but this is from the same game and is the saddest theme ever. Emil- Sacrifice

Whoa, all of the already posted boss music are awesome. Keep this thread going with more boss music, as a DM I need lots.

I'm going in with the classic J-E-N-O-V-A from FFVII. A tune that got the action going through the whole song.

Seymour from FFX also got an awesome tune.

Both Super Mario Galaxy final boss tunes are hot, but I like the one from SMG 2 better.

For the BEST boss fight music? I think I have to ponder some more on that one.

A chant that says "Cena sucks! Cena sucks!".

Here is the aforementioned final theme of Gongora. Howl of the Departed.

And just because the level itself if a boss in and of itself (I still have trouble just getting to the end, much less getting past the second checkpoint) Bloody Tears