Buildings Old, New and Derelict
Buildings often make wonderful photographic subjects as they are always interesting not only for their aesthetic beauty but also for the questions they pose. You can see a building day after day and it does not register as something worthy of photographing but then perhaps you see it in a different light or as a reflection or it is glimpsed through trees and then to your eyes it becomes something you want to photograph to capture that moment in that building's life.
Some buildings are just works of art from the beginning.
I also like shots of doors and windows and empty buildings (though there are not a lot of those that one can gain access to in New Zealand).