A house? It sounds funny! Well. Not only a house. A small terrain which is yours. And you could change its theme.
Let's say it's a small insland. Only a small house, with a calm music and a lil spot for a garden It's green, it has flowers, blah blah... Eh, you could change it!! From Spring to Winter, for example. Everything to be covered in white and ice everywhere. (This would be outside the house) Inside the house, you could put things (A small bed, a lamp, a table, a carpet... Probably a small picture on the wall). It should be small because you don't have many things to do there. Just to stay AFK or to stay with your friend(s) there. In a corner of the small house, there could be a small warehouse (a deposit) where you can put there Items (Weapons, Armours and Zeny...) and you could be able to share it with all your characters of your account. It could look like a box or a chest. Not so huge, because the house is pretty small. Haha!
Eh, it's just a small idea