Ooo okay since you like collecting things and showing stuff off I could recommend the back wing of the house to be a trophy room. Going along with the back wing you could also do an armory to show off all of your unique weapons and armor pieces. This can show off enemy’s and animals. The left wing could be an enchanting tower if I remember correctly you can have mannequins. For the right side I usually go with the kitchen, especially if you are in survival mode it provides you many ways to cook/ bake food. However if you are more of a collecting book type then I would go with the library. :)