Your main bedroom.
The room features a sorting chest for the Fate cards and jewelry some chest's to store whatever you like and large dresser's. the back dresser has a hidden panel that leads to a secret vault. The vault can store Septims and will dynamically display your wealth stored up to a value of 2 million.
There is also a optional mod Dovahcloset that can be used to sort gear and costumes in this room and enable you to quickly change between preset outfits.
The back door leads to the Hot_springs a upgrade for them is also available at Bits and Pieces in Solitude.