Years ago the typical tower speaker was three feet to four feet tall and was probably a good quality 3-way speaker at best. Today, tower speakers might go to five feet tall and be a couple feet in width. They might actually include several drivers beyond the old standard of three.
The positive of tower speakers is they are noted for deep, rich sounding bass and literally filling a room with sound when powered correctly. Due to their large size, they still serve as a benchmark for other full range speakers.
With the many advances in audio and video electronics, it is possible to team up a good pair of tower speakers with subwoofer to literally present a complete wall of sound. If this is done correctly, the listener benefits from high-quality sound representation which seems to fill the entire room regardless of position. This setup can actually make the entire wall seem like the speaker system.
The downside to tower speakers is what gives them their high sound quality and deep bass. They tend to be very heavy due to the multiple speaker installation and cabinet and require substantial power to drive them properly. They also will be among the most expensive speakers to purchase in most cases.
But if you can find room in your budget, a top name tower speaker from the likes of Infinity, JBL, Yamaha, Polk or Boston Acoustics is a great foundation for a home theater system or just a great home audio system.