So was replaying MGS3 there and I'm fighting The End.
It brought a slight feeling of nostalgia at just how fun this boss actually is and why he's probably my favorite.

1. No cheap mechanincs:
He doesn't have a massive HP pool, He doesn't regen health, He doesn't use cheap OHK moves, He never takes control away from the player.

2. Rewards careful players:
I love this one. When you run around in the jungle like a fool, you get sniped. When you take your time to find his poistion, sneak around him and hold him up, you're rewarded.

3. Unique ways to beat him:
I've not seen this done in any other game, but allowing me to kill a boss before I'm supposed to fight him and then the game accounting for that is cool. Also beating just by waiting is pretty cool(Cheap as hell though).

4. Sense of accomplishment from beating him:
Just the fun of stalking and after a while taking that fatal shot, makes me feel good.
I out-witted him at his own game, not just button mash or just DPS him.

5. Rule of cool:
Snake vs An old veteran in a Jungle sniper battle. I like it.


So what's your vote for the best boss fight? Give reasons as well!

Shadow of Colossus, it's just one massive boss fight after another.

Also Deus Ex (the original) since you could win the boss fights against Anna and Gunther by careful preparation beforehand.

The final boss of Tales of Vesperia. Starts off semi-challenging, then gets very difficult. Better yet, if you collected every character's ultimate weapon, that unlocks a secret third form for the boss, which kicks your ass even harder. Definitely not a disappointing end battle (which so many RPGs are guilty of).