When the fuck did he turn into a fucking dragon? This is Fable we’re talking about, right?
Ocarina of Time - Final Ganon battle. Not because it’s particuarly difficult (attack tail, light arrow face, repeat), but because of the music. Best boss music evar.
Metroid Prime had a few really fantastic battles from what i can remember… it has been a while since I’ve played though.
I’m sorry, I had it all wrong.
THIS is the greatest boss battle ever!:
https://www.youtube.com/watch?v=JXQrCwGCp-I
All the bosses in Conkers Bad Fur Day
I just had to say it :3
Is it just me or did Pandemonium come out in 96 and not 89.
Yeah, at the very end, he does that. Either he turns into one or his mind takes over the body of the dragon, but whatever, he’s a dragon 
Oh if only there were epic Crab Battles in MGS3… I would have died happy.
Daddy Bowser - Mario 64.
All bosses from Secrets of Mana
Its Fable - The Lost Chapters, the very last boss fight
That was fun. Fable rocks.
All Boss fights in Painkiller
Nice bump answering something I had already answered 
The boss fights from Twilight Princess are pretty fun, except when you fight Ganondorf. The fight in Ocarina of Time was awesome but here it’s…boring. Not much fighting from Ganondorf so it’s not as epic.
Andross from Starfox 64 has always stood out in my mind. Partly because when I first beat the android version I was so young the evil laugh he had actually scared me to death and partly because of the surprise when you later find out there’s another “real” final boss battle that’s even more epic. I mean come on! It’s a floating brain that looks like a giant mutant jellyfish, it doesn’t get much better.
Im not even kidding.
My favorite boss battle really is against the Nihilanth. Really. It is.
My second favorite boss battle is RAAM from Gears of War 1.
I like boss battles where at first you dont know how to defeat the enemy, and even when you figure out how, its still a challenge. Defeating the Nihilanth is now easy on hard difficulty, but RAAM is still quite a challenge on Insane.
Final Fantasy VII, VIII and X are some awesome fights.