There was a time, quite recently in fact, when the most important attributes of buildings were their aesthetic qualities, fitness for the intended purpose, and structural integrity. However sustainability objectives - paying closer attention to the soundness of the architecture from the perspective of the environment - are quickly becoming the overriding factors in contemporary home plans.
In fact, cottages - by which is meant small, asymmetrical, (usually) rural dwellings of one or two stories and stone, brick, or stucco exteriors, come in a large variety of architectural styles. European-type cottages can incorporate design traits from Tudor, Georgian, French, and Italian architectural styles, with open rooms and high ceilings, fireplaces, and even luxurious elements such as gourmet kitchens, formal dining rooms, private master bedrooms, and French doors. What all cottage styles have in common is their livability - their human scale and design for relaxing, unstressful enjoyment of life.
For example, in the southern United States sunshades and louvers as well as light colored building materials for roofing and cladding help to reduce the heat gain. Sustainable design also means that every inhabitant has access to outside views with natural light and natural ventilation. This sometimes results in narrower floor plans, or articulated plans which expose interior areas to several exposures. The contemporary house plan is designed with the goal of reducing fossil fuel consumption, and providing a healthier and relaxing environment.
Plan your budget accordingly so that you don't get your hopes too high or settle for less than you deserve. That is, plan your budget based on what you can afford. If a half-million dollar home is in your dreams, make sure you can finance it - visit your accountant and bank manager beforehand so you know what budget you can realistically work with.