Baseboards are installed partly for aesthetic reasons: Just as crown molding hides the area where walls meet the ceiling, baseboards hide the joint where walls meet the floor, which might otherwise be unsightly. But baseboards also serve a very necessary function in protecting plaster walls from getting kicked or scuffed by shoes, boots, and vacuum attachments.
In general, the design should tie in with the room’s other trim. All the trim should be part of the same family, with similar detail and proportions. Baseboard trim is usually much less ornate than crown molding, though in modern houses both can be starkly simple. Remember that more streamlined molding will collect less dust and dirt. And since baseboards are adjacent to the floor, you need to make sure the two materials work together in terms of color and texture.
Because they must stand up to a lot of punishment, most baseboards are made of solid wood. But composite materials like MDF (medium density fiberboard) are sometimes used, since they’re less expensive and resistant to mold and mildew, if water intrusion is an issue.
The classic method of choosing color is to use white for ceiling and trim (baseboards and window and door casings), and then paint the wall a color or hang wallpaper. Though if you are looking for a more simple look, you can paint the trimmings to match the walls.
Another option, especially for hardwood baseboards that match the floor: staining or finishing them in the same color as the floor.