For most gamers and regular users those mATX cube style cases are more than enough. Most of the people buying full tower cases are doing so for aesthetic reasons. Like most of those guys with lifted trucks and huge tires. If you had three GPUs and eight hard drives you'd need a full tower. If you had an open loop liquid cooling system running to all your parts with a huge radiator and reservoir. You'd need a full tower. A good mid tower is more than enough for 2 way SLI, a couple of hard drives, Optical drive, SSD and closed loop liquid cooler for the CPU.