The Shadow Queen from Paper Mario TTYD. She/it was epic.

Ganondorf from Oot,it was a very epic moment.

Psyco Mantis even though he wasnt hard it was a mind blowing battle made me think differently of what games could do.

You can refer to my blogs for the top 20 best boss fights ever LOL it may help you a little

I vote for the final battle in galaxy for its epic music and hard difficulty(on luigi).

Banjo kazooie and banjo tooie final bosses, great mighty poo, K. Rool in Donkey kong 64, Some of the skies of arcadia legends bosses, you named alot of the good ones up there

Mother Brain from Super Metroid
Ridley from Metroid Prime
Shadow Queen from Paper Mario 2
Bowser from Super Mario World 2
Twinorva from OOT
Ganondorf from Twilight Princess

Halo bosses are freakin' cool but easy (they are not my fav. though)

Well the Bowser 64 stands out for me. During my N64 phase I really remember finally thwarting that evil King of the Koopas.

the ones u mention r good.

Magus (Chrono Trigger/SNES): The first time, I can remember, fighting a boss that would later become a member of my party. He had an "I am the embodiment of evil" look about him so I really didn't see that coming.

The Colossus in SOTC where it pulls you under water. (The flying one.)

The robot-spider from Metroid Prime 2. Other than that my mmind is kinda blank.

Bowser from Super Mario World is very memorable for me since it was the first video game I ever played, and of course Ganon from OOT. I can't think of any others right now, I'm to tired, lol.

I have 3;

The Chief(Re4): Seriously, this boss the image of, "WHY WON'T YOU DIE???"

IT(Re4): Yes, Re4 again, but this one wouldn't die either! The best part was the beginning where you had a time limit to get from one area to the next, that was so much fun.

Boss Dragon(Air Temple) LOZ:TP: This battle had awesome music, and the best part was when you had to get on its back and slash on its neck, that gave SUCH and adrenaline rush.

pyscho manyis was so cool and the Boss it was cool.

Mother Brain, Super Metroid.
How about Dark Samus, the first time Samus encounters and fights Dark Samus?!

Um... how about Dr. Eggman - The final battle, Sonic the Hedgehog 2.

Cacletta from superstar saga! jk that one was cool though. Many different Bowser battles are my favs.

O.o im surprised only one person mentioned shadow of the colossus almost all of those fights are epic but i would have to go with the 16th that was insane dodging fireballs while trying to get to the giant. If your not familiar with the game here's a wonderful link! http://www.crunchyroll.com/forumtopic-395761/which-was-your-fvaourite-colossi-battle/

I have thought about shadow of colossus, I just can't decide which one.

Most of the bosses in Little King's Story are absolutely amazing. However one that REALLY stood out to me was King Jumbo Champloon. You just beat the sh!te out of him to kill him, but the environment design, his attacks, and the design of Jumbo Champloon was so engrossing that even when you were getting your a$$ handed to you on your 10th attempt at beating him, you couldn't help but have fun. Everything about the setup was just perfect, the extreme difficulty, intensity, his attacks (and recoveries), all his little Onii helping, and the music, especially the music. It all added up to one epic fight. King TV Dinnah was also a very unique boss and the final boss was neat too.