A good size home computer tower is a tower that is called "Mid Tower". A mid tower computer is 17 inches high, 8 inches wide, and 17.5 inches deep. These types of towers are the most common towers available and are capable of fitting a wide variety of computer hardware in them. If you are looking to purchase a mid tower case without any components for a custom build, I recommend purchasing the Antec 900 mid tower case as this case comes with numerous fans built in to help keep a constant flow of air in your computer.