I love every single one of the "Age of Wonders" games. They're spiritual successors to the old "Master of Magic" game which is an absolute timeless masterpiece.
Think of a Multi-layered map with above and below ground possibilities, Turn based movement, Civilization Building, Hero Building, and then you have combat. Instead of Civ style resolution, when armies meet together, it goes to a smaller map mode where all your units can use their powers and maneuver, all in a turn based manner (as well).
They're all worth owning from a gameplay standpoint, but I feel that AOW2 is probably the weakest of offerings. AOW, AOW:Shadow Magic, and AOW3 all really scratched my itch.