I tend toward roleplay for all my nations even in mp dom3 games.
My favorites for roleplay would be Pangaea, Marverni, Tir na n'Og, Arcoscephale, Caelum, Kailasa/BadarLog, early Ulm, Marignon. Oceania.
I have seen and very much understand the RPG factors for nations such as Ermor, R'lyeh, Sauromatia, C'tis, Hinnom, Tien Chi but the appropriate attitude for those just doesnt match me. I cant seem to get into them altho I do appreciate it when someone else in a game Im in does it.