It's cheap and convenient in more ways than one. Because it's so dark, decorating with soul gems, dynamo cores and other glowing items really make the place seem magical. I love stonework and it feels like your living in a big, safe cavern. It's got a huge library, a gorgeous entryway, a living room with attached dining area, a kitchen with attached dining area and a big bedroom. It's got an enchanting lab/armory and a separate alchemy lab.
It's big and dark with Dwarven architecture and it's got lots of places for weapons, shields and one armor mannequin. Vlindrel Hall in Markarth is my favorite. For the houses that you can buy, here are my rankings: