Boots of the Mystic didn't appeal to me much, but I had a whole set of snake/spider based items which I used to great effect earlier in the game. I also picked up a lot of pirate/robber based items but never really tried them out
Looking at the list of boots ( funnily enough the Bronze boots arn't on there :-/ ) the "best" are probably:
Kerian Shoes - +3 defense ( meh )
Knight's Boots - +300 Leadership +5 to the Defense of Swordsmen, Guardsmen, Horsemen, and Knights ( would make me consider humans in my army :S )
Twinkling Boots - 15% physical reduction