If you are intending doing it up to sell on, then as felix says keep it pretty cheap. A mate of, well ok, acquaintence, of mine does the following.
Installs a very cheap wooden kitchen, with cheap stainless steel appliances if the old one is naff.
Puts in a cheap white bathroom, with white tiles, and cheap accessories if the old one is naff.
Put the cheapest possible laminate flooring down.
Paints all the walls the same neutral shade.
Then he dresses the flat / house. Puts in a state of the art surround sound system, with large flat screen telly.
Luxurious cream leather sofas. Very expensive furniture
Really expensive small kitchen appliances, i.e top of the range coffee makers, food mixers, toasters, pasta making machines, knives .... you get the picture.
Puts his apple / iPod / iPaq / Laptop, state of the art of course in the study.
When he comes to sell the place, for the price of one cheapo kitchen / c**p laminate floors, lick of paint, he clear a very substantial profit, such that he has no need for any other employment. Of course onnce it's sold, all the expensive stuff goes, leaving the new occupants with a magnolia coloured shell.