Gyorg was definitely my favorite boss. I enjoyed his manic and unpredictable movements as they offered an element of terror to the fight, which I feel is too often absent in Zelda bosses (especially recently, although Koloktos sort of helped that situation). I also liked Odolwa quite a bit, but Gyorg almost offered a challenge, which makes me enjoy fighting him a bit more. I really disliked Goht and Twinmold as I found them very easy and pretty boring. I would say Majora, but honestly I thought the fight was a tad lacking, despite the boss himself being delightfully insane. I imagine my opinion of that fight may change if I ever decide to do it without the Fierce Deity mask...