Korneil's idea of manic 5 is great.
My school because its built like a compound and all the walls are in concrete so there would be no damage. In fact, any school would be awsome because of the long corridors and the empty rooms, just too many places to hide.
Since this is an imaginary scenario, an oil tanker. One team would be underwater and have to climb abord while the other would be "terrorists" and be on the boat. Airport is a great idea too. Inside a packed night club, with the music and lights going ala collateral style would be cool too.
Ooo, heres a good one, a hotel, with all the floors open to the game, thats alot of hide and seek.