1)The End (MGS3):
If a boss battle has to be a fight with a lot of tension and a high intensity choreography with quick reactions this one surely made it right. We only have to see the ambientation of this boss fight and how your enemy is going to fight with you to understand the big problem you have... it's a sniper battle.
You have to be extremely silent and careful when you're hiding from him... of course that's because the first one who found the other will win. As a personnal experience the fist time i play that boss fight was very frustrating because he doesn't kill you, he just make you fall asleep so if you lose, you're going to spawn very far from that place so you're going to waste a lot of time reaching it... by the way he can die of old so that's maybe a good thing but you're going to feel very disappointed in yourself (as i did).
2)Colossus of Rhodes (God of War 2):
What can i say about this big guy, it's the first boss in this game and he chases you all over the city, i really like the music of this battle because it really fits the stage so you can enjoy a lot this fight.
3)Liquid Ocelot (MGS4):
The final battle in Soild Snake journey, it's a good end in the saga because it has a lot of memories from the other games and battles from the past agaisnt him. ¿Still not convinced? well, every time you made enough damage to him, the music and fight styles changes to one of the other games of the saga (MGS1 to 4) so it's a nostalgic moment to old school players.
4) Manus Father of the Abyss (Dark Souls):
This DLC final boss battle is one of the best of this game because it's not only difficult to beat (he is indeed) but he has a lot of backstory that makes you think about all the lore of this game (which is difficult to understand). You can easyly complete this game without understand anything about it but if you do, you can understand why this boss is very important not only for the plot, but also for the story of some characters like the other bosses Artorias and the wolf Sif.
5)All the Colossus (Shadow of the Colossus):
I just can't decide wich one is better, every single of them have a unique play style and strategy to beat, as the previous boss in this list, they have a backstory together that you have to discover by your own. Every colossus has a different ambientation and elements they use to fight against you, you have to found their weikness and destroy them in order to win all matches so good luck.
There are a lot more bosses that i have beaten in videogames but i'm going to start with those, maybe in another ocassion will make another list, but for now those are my best, Thanks for reading... see ya!.