Keep in mind a few basics about floor plans as you inspect houses. Stand in the entrance and try to imagine yourself going about the daily routine. Consider, for example, a hypothetical trip home with bags of groceries. Where will you park? Will you have to carry the load up stairs? Must you go through the living room? Is there a handy counter near the refrigerator for unloading?
If you have an infant, you sleep with your door open, and you want to stay within earshot. In a year or two, though, you will value a private, quiet bedroom. Check whether the master bedroom is separated from the others by a zone of closets, hall, or baths. (The best floor plans incorporate such buffers for all bedrooms.)
If the front door opens directly into the living room, a house in the North will eventually need a small enclosed foyer to shield the thermostat from icy blasts. Then imagine yourselves in mid summer, eating out on the enclosed porch or patio. Will it be easy to serve from the kitchen, without risking spills on the living room carpet en route?
Check the kitchen for sufficient counter and cupboard space. Double-check for a place to put things down, not only next to the refrigerator but also at the stove and sink. Even if you are resigned to a small Pullman kitchen and plan to eat in the dining room, look for enough space in the kitchen for a high chair, or a stool for a chatty guest.
Give a house extra points if you don't have to go through the living room to reach other areas. A dead-end living room makes for relaxation and tends to stay neat. Look for the convenience of an outside entrance to the basement and a small outside door to the garage.
An engineer's inspection can help you evaluate condition, which is particularly valuable with an older home. But you are the only one who can judge whether a floor plan fits your lifestyle.