Let me think:
Shaka, (outside of civ and one 10-minute period in my Honors Modern World class, I have never heard him mentioned)
Xerxes, as there are plenty more possibilites for a Persian leader. There have been plenty of empires that are considered Persian (Persia, Safavids, Parthia, Sassanid, Seleucid, Khawarizim, the list goes on and on and on...)
Suryavarman, as his leaderhead is insanely irritating.