A few of my favorites: Angelique's bedroom at the old house in 1795. The humble little servant's quarters, and she would always be in there casting a spell or laughing at Ben for thinking he could disobey her.
Jeremiah's bedroom in 1795. That huge canopy bed, big fireplace, model of a ship over the mantle, that place was beautiful.
Dr. Lange's office. Another really elegant space. Even had harpoons on the wall.
The tower room at Collinwood, also 1795. When Joshua found out Barnabas' secret and moved his casket up there, and people started noticing a light coming from up there. That was always cool.