I'm a bit sad that there are no Liches in skyrim, perhaps at the end of a dark necromancer lair, or a dungeon boss. I guess Dragonpriests are basically the equivilent of liches, but it isn't the same. I liked the lore, and darkness that surrounded Necromancy in oblivion, and that isn't in this game. The only logical explanation I can find, lore-wise why there are no Liches, is that somehow in the past two-hundred years, the recipe for becoming an undead lich became lost. Maybe, they'd introduce Liches in a DLC, or something? I don't know.