Haven't played since February and going to buy Skyrim for Pc, what are some fun character class/builds to use?

I remember having an assassin who was well trained in alteration and illusion. He carried one knife in his left hand and his spell in the right. On the rare occasion of being found he would cast a spell that made him invisible, and from there he could play with the enemy's minds. They would attack their own allies while he hid, crouched in the corner. When there was but one left, he would draw his bow and let the arrow glide through the room, silently through his head.

That was my favorite build. Please share some fun class builds you used!