most enjoyable would be makedonia... i mean its fun... u can go either way (no sexual pun intended)
to iberia and destroy the barbaroi romani or to the east and claim what is rightfully yours as the true heir to makedon and so must be king of all makedonians :)
then you could go northeast and have a bosphorus kingdom?
endless possibilities

but to be sure, I'd think im torn on the next campaign as Baktria or Epirus as they have both unique rosters and new tactics other than anvil and hammer (immitation legions, horse archers etc)

Looking forward to that and EBII after i get my new comp XD