Let's continue =)
Number 5- Sin (Final Fantasy X)- It looks like the monser from Cloverfield, wonders the land killing everything in it's path like a hurricane, and is actually your dead father. I didn't even fight it yet, but I know it will be awsome =]
Number 4- Colossus #10ish I think (Shadow of the Colossus)- Every single colossus would be on this list, but I narrowed it down to one. The huge dragon that flies around the dessert and burrows itself underground was the winner. You would wound the thing to slow it down, then ride along side it on your horse and jump off and try to cling on for your life on its wing.
Number 3- Ganon (The Legend of Zelda:Windwaker)- You really couldn't even attack him, and his attacks can take 5 hearts with one blow! Zelda would tell you to get him in the right possition to damage him with light arrows, then while weak, you would attack him. Half way through, he knocks out Zelda and it's up to you to finish. The fight was fun, but Ganons defeat was crazy! Impaled in the forehead by a little childs sword...
Number 2- Bitoriz Mendez (Resident Evil 4)- You have low health left, and then...Yes! You beat him! Now to save Ashely and...Crap! Just when you think he's beaten, he transforms into a giant millipede zombie thing that can take you down in one hit if he gets the chance.
And finally, Number 1- The End (Metal Gear Solid 3)- This isn't really a battle, it's a game of stealth and hunting skill. Time to but all that stealth and survival stuff you learned in the wild to use. It's a sniper battle- You have to seek him out, but he almost always knows where you are. He is the forest, and knows everything. It was the first boss fight that pushed my thinking skills to the max. I'm usually a charge and kill type of person, but that's not possible with this fight.
Mewtwo (Pokemon Blue) One of the first bosses I fought. Wanted to catch it, but used my Master Ball on Zapdos instead.
Pyramid Head (Silent Hill 2)- The thing doesn't die easily, appears when you have a speck of health left, and is the freakiest video game character ever thought of.
Sephiroth (Kingdom Hearts 2) I was on lv. 50 my first time, but was murdered. I did some level grinding until I was level 80, and beat him almost instantly. It was fun, but short-lived.