You don't have to go to the extremes of one wealthy matron whose home has several bathrooms nearly 20 feet square, replete with gold fixtures, antique furnishings and art work. But if you improve your existing bathroom or add a second one, you could be making a wise investment. Modernized kitchens, with cabinet and counter space sufficient to contain all the paraphernalia of our 90's cooking style are also good ways to boost market value and salability. Openness and light get top billing from brokers and professional renovators. Skylights, sliding patio doors and enlarged windows all increase salability enormously.
Fireplaces get top marks too in increasing salability.
An extra bedroom, particularly in a two-bedroom home, may increase salability. But it may not raise the market value of your house more than the cost of adding it in the first place.