Actually, good liches get Turn Undead as a cleric of their hit dice, unless they're already a cleric, in which case they get to turn undead as if they were 2 levels higher. Also, they are immune to Turn Undead, but are destroyed by rebuke undead. There are also Lichfiends, who are demons and devils that become liches, gaining more power than a normal lich. If I had a very old character, I'd certainly consider becoming a lich, but just to live forever, not anything evil, he wouldn't plot to conquer the land, just to conquer the nearest cookie factory.