For me:
Best - A heavily armored warrior in Blades Gear with and Ebony Greatsword. I love the block/bash mechanics in the game.
Two-Handed, Block, Heavy Armor, Restoration, Enchanting, Smithing
Worst - Conjurer/Illusionist. Just goes completely against my playstyle, way too "passive". Summoning atronachs and furying everything. Powerful but just not for me.
Illusion, Conjuration, Light Armor, Sneak, Restoration, Alchemy