The Extreme - Nobuo Uematsu, from Final Fantasy VIII Original Soundtrack
Maybe it's because of the overly exagerated negative stigma the game it comes from has due to the internet and the nature of bandwagoning, or because it came directly after One Winged Angel and, before that, Dancing Mad. Or maybe because the villainess it was attatched to was completely underutilized despite being a potentially great idea if used differently (which describes FFVIII overall, really...). Whatever the case, I always thought this was a criminally underappreciated Final Battle theme. I would love for the Distant Worlds tour to do a proper full version of this song because it would be amazing to hear the entirity with an orchestra and choir. The Black Mages version is interesting and cool, but it's not quite the same. This pretty much goes for all Final Fantasy games, but whatever issues the game had (both real and imagined) the soundtrack was definitely a bright spot for all except those who looked for ways to put the game down. Actually, I remember an old list by a bunch of FFVII fangirls that had reasons why VIII was a worse game, and while they stumbled onto a handful of real ones (deranged pacing, quickly loses focus or is misfocused on what it should've been, badly entered plot elements) most of them was stuff like "There's too much CGI, it's not special anymore" or "They made the characters more realistically proportioned, it takes the imagination away from the player" and other stuff that's msotly reaching.
Anyway, regardless of my affinity for the game, this is a good song from beginning to end. So are Ultimecia's other two songs as well.