When you bought a house, did you make it just a house, or did you make it something more than that? This is what I've done with all the houses I currently own.
Celestial Observatory: Main house with teleporters leading to other houses.
Massive Fantasy Palace: Fair Grounds. Still working on the inside. Possibly will be a large maze
Winter Wind Tower: Museum of the Spiral.
Wooded Cottage: Restaurant.
Royal Playhouse: Storage for extra furniture and holiday items when not in use.
So there you have it. What have you done with your houses?
I have mostly just decorated my houses using different glitches that blend into the decor such as adding a statue in a fountain or ships in water.
In my ice house I do have a ship wreck. I put a ship partially in a large rock and floated wooden planks around it.
While waiting on Azteca, I decided to craft every piece of furniture in the spiral not counting the housing games. I put all those items in my dragon fjord house. I am now in the process of crafting the Khrysalis furniture. The problem is not having the space to place them inside the house. I got the item count high enough just no room left In house. Will have to make a few adjustments.
I also have several houses on my wizards that are just storage for pets and furniture. For some reason I find it difficult to sell housing items.
At the Island getaway, I turned it into a resort with a dojo. Many little blue cyclops like to vacation there on the beach. I once met someone called Morgrim, who had the Death House decorated as a pet museum. There were pets up on pedestals and in separate rooms, or corrals outside. There was one kind of pet in each place, a room for spiders, corral for dragons etc.. At the time he had almost all the kinds of pets that were available.
My Grand Fortress is a Mally/Sylvia shrine. All my DS-themed stuff, plus my Ruined Painting and all my weapons are there. And I have a bobble-head of each in a corner :)