I'll pick Byzantine just on the knowledge that they have Dromon, my fave unit from Civ III. Also I want to try out first a civ whose units/buildings are in the early era. A small map first, just not to get too overwhelmed. I'm also excited to try out archipelago map with naval colonial civs (England, Spain, Dutch, Japan) just to try out the promised more aggressive AI use of naval invasions. ALSO all the three scenarios interest me a lot!