EASIEST - SHADOW TEMPLE I can go through the Shadow Temple like it's nobodies business.
Not only that, but I can defeat Bongo Bongo in a matter of seconds, which makes this temple even easier.
HARDEST - WATER TEMPLE This is the only temple in the game I have to complete before I quit the game. I can start any other temple half way through with no problems. I can never remember which keys I've gotten, which skulltula's I've gotten, or what I had the water level set to before I quit. The only thing I like about this temple is Dark/Shadow Link. That battle has to be one of my favorites.
I also really hate fighting Morpha. Morpha is seriously the most difficult boss in the entire game, in my opinion.
MOST FUN - GERUDO TRAINING GROUNDS I absolutely love how it requires you to use almost everything you've learned throughout the game. I know it's not really a temple, but I love being in there.
CREEPIEST - LORD JABU JABU'S BELLY I hate the bubbles, I hate the jellyfish, and I hate how everything inside him is alive. Creeps me out and I hate being in there. I also hate how you have to carry Princess Ruto around everywhere you go.
And that giant Octorok or whatever it is scares me. I don't like it when he sneaks up behind me lol.
FAVORITE - FIRE TEMPLE/FOREST TEMPLE/GANONS CASTLE It doesn't take me much to get through these two temples.
I also really like the mini bosses in these two.
I really like going through Ganon's Castle. It's fun and the two final fights are probably my most favorite in the entire game. They're also pretty simple, especially Ganon.
How I wish the game would you fight bosses again. :(