1. The Egyptian Empire - It was the main influence of the following European empires unto this day, and the kids still love anything Egyptian.
2. The Roman Empire - Dominates modern thought today
3. Byzantine Empire - Triggered the universal importance of writing and the alphabet to common use
4. The British Empire - Biggest empire on earth ever, that has military influence on all nations
5. Ottoman Empire - Was at the center of the world's conflicts for over 500 years, and shaped many of the states around it
I am not one for numbering history down to any given list, but I'll go with it for the purpose of this thread.