Your rabbit won't need a ton of room, but its cage or pen should be at least four times the size of your rabbit - more if it is confined for a large amount of the day. Your rabbit will need enough room to hop around a little bit and stretch out periodically.
Rabbits are not designed to live on wire floors - it is hard on their feet (which have no pads, like cats or dogs). If you must use a cage with a wire floor, you need to provide your rabbit with a resting board or rug for her to sit on, otherwise it will spend all of its time in the litter box. You can find cages with slatted plastic floors, which are more comfortable, or you can use a solid floor. As long as your rabbit has a litterbox in the corner that it chooses as its bathroom, there shouldn't be much of a mess to clean up.
Adequate ventilation is a must regardless of what type housing you use. Respiratory diseases can arise without good air flow. Make sure at least a portion of the cage or hutch is constructed of wire mesh to allow for good air flow.
Size will vary according to the size of your rabbit. Recommended size for one doe and her litter:
Small Breeds 2-4 lbs - 30" X 30" X 12" high
Medium Breeds 5-7 lbs - 30" X 36" X 12-14" high
Large Breeds 8+ - 30" x 40-48" x 14-16" high
Self-cleaning cages, where fecal and urine matter drop through, have a floor made of wire mesh or grid that forms squares. It is important to provide some type of catch tray or method of collecting the rabbit's waste. Trays can be lined with paper, wood shavings, or other absorbent material. Adding a small amount of baking soda to the litter will help eliminate odors. Some portion of the cage floor should be solid to help prevent the rabbit's feet from becoming sore.
Cages must be cleaned frequently to prevent odors and disease. A good cleaning/disinfecting solution for utensils, equipment, and cages is one tablespoon of household bleach mixed in one quart of water. Then scrub and rinse well. Droppings should not be allowed to accumulate under the cage and should be raked up weekly.