Just curious about everyone's favorite boss; BTW, please provide an explanation.

Mine has to be Miraak; he uses a large variation of shouts, and uses different weapons, I haven't encountered another boss who has three stages.

This should probably head to the C/H/S section. Just because we will probably end up discussing many spoilers in the process of explaining our answers.

My favorite is Alduin. Looks so awesome.

Similar thread not even a few days old.

http://www.gamesas.com/topic/1463899-toughest-boss-fight/page-1

Regardless, Karstaag for me.

That would be most difficult. This is your most enjoyable.

Karstaag was the most difficult and enjoyable boss fight for me.

Draugr Death Overlords, because they carry Ebony Weapons at level One. That Frost Troll is My second favorite, I consider It a test for My characters.