From an interview with Sarah Susanka about her new book, Not So Big Remodel in the Washington Post:
Can you give an example of the most cost-efficient remodel a person can take on?
The kitchen, if you do it sensibly. If you can tackle that part of the house, it will not only be good for resale but also will dramatically improve your life within that house. The kitchen is the hub of a house, and when it is connected to the eating area and the main living space, that interconnectedness is extremely desirable.
What are some of the places where costs start to go up without much benefit?
Often people think they need materials like granite countertops. But what’s more important is the shaping of the spaces; it’s the connections between rooms that will make you feel more at home. I used Ikea cabinets in my kitchen, and for most people’s purposes they are vastly superior to what was in the house. The cost of materials doesn’t have to be exorbitant for good design.