I always liked The twilight princess boss fight on the bridge against king bulbo (or whatever his name was), i loved the style and riding on horse back and also the location.
Stallord. Maybe the most fun and exciting boss ever in Zelda. So unique.
Ganon OOT. Just because its OOT.
Ganondorf WW. Jamming your sword into his skull will never get old and is one of the most shocking scences ever in Zelda.
Whenver you fight Ganon as the final boss in Ocarina of Time. That fight gave me chills and I absolutely loved it. It was like bringing Zelda back to its roots.
Argorok, the dragon in the City in the Sky from Twilight Princess. It was ridiculously fun and the stormy atmosphere was one of the main things that made it even better.
WW ganondorf. the flooding background is an epic battle scene and his movements make the AI seem like it's learning and developing defences to your attacks. plus the sword in the head is epic as well.
Jahalla because he's the boss in those zelda games that u have to beat creatively. He was fun to slice up in four swords adventure, and fun to destroy his little poes that made up his body in the wind waker. THUMBS UP
I liked the Tp bosses Stallord, Argorok, and Zant. Zants battle was cool cause of all the different phases. Although the most intense battle was definitely Ganondorf.
Gyrogh from MM is one of my favorites and I thought it felt like the movie Jaws. Very intense knowing something's under you and your trying to climb up to saftey.
I'm going to say Demise. I'll admit when I first fought him, I had trouble figuring him out. But the lightning, epic music, and climatic finish makes it one of the most memorable final bosses in recent history.