Since basements are generally surrounded by earth they remain at a stably cool temperature year round. Before starting a remodeling project, you must brainstorm what you would like to make it: a playroom for your children, a home office, exercise area, a large shower place, a guest space, etc. Consider all of these before you start the work. Many people like a kitchenette or a wet bar.
You must also consider the disadvantages of basements: small windows, low ceilings structural columns, etc. Basements should be more heavily lit to maximize both natural and artificial lighting. If you want to maximize the lighting, you can create an open floor plan, very big windows, or a French door to the basement instead of a solid door. You should also consider light colors, and mirrored walls or ceilings.