Generally speaking Floorstanding Speakers are the go to speaker for a hi-fi set ups given their wide frequency ranges and simple 2.0 mentality.
Generally speaking floorstanding speakers have one or two mid/ bass drivers and one tweeter. This allows for greater control and balance of mid/ bass and high. This separation allows each driver to work independently on different frequencies which means each driver has to work less hard. Just think how that cone is moving so quickly to reproduce such a wide spectrum of sound. Now imagine you split that sound out by two or three frequency ranges. As you can imagine there is less chance of distortion and far less movement needed by the driver to achieve the high/ mid/ low.
Another benefit to the floorstanding speaker is that they have all the sound you want in one box. There is no need for additional subs to supplement the bass. Floorstanding speakers often sound very cohesive and connected as all the frequencies are resonating from one place. Sometimes additional subs if not matched well can sound delayed, muddy and cumbersome.
Floorstanding speakers are the 'all in one' speaker that produce high quality sound across a wide range of frequencies. Often simplicity is best!
Not only do floorstanding speakers have larger drivers but they also have larger cabinets. Each cabinet acts in a similar way to how humans reproduce sound. With humans it's not just the vocal cords (Larynx) that generates the sound but the whole mouth, neck, tongue and body as a whole. Although speaker cabinets aren't nearly as malleable as our voice cords, I'm sure you can appreciate how different cabinets can change the overall production of the sound.
Given that floorstanding speakers have the benefit of the larger cabinet/ drivers/ cones, this enables them to products much deeper and heavier bass. Quite literally the 'body' of the speaker defines the output of the sound.
Before we go too far, floorstanding speakers aren't like PA systems. They will never compete with night clubs or the likes of, however generally speaking floorstanding speakers are much louder than bookshelf speakers.
Recently I was showing off our Monitor Audio PL100's bookshelf's vs our Tannoy DC10's floorstanders. We used the same pre/ power amps on each set up. Overall the results were quite phenomenal. The Tannoys were almost twice as loud.
Why? Well firstly the Tannoys have four 10" cones in comparison to two 6.5" cones on the MA's. Secondly bookshelf speakers are sometimes less efficient, and in this case much more thirsty. Therefore you need amps which can handle with this resistance. This therefore allows the amps to drive the Tannoys at a more fierce rate. That being said, you should always check the wattage/ omhs before buying any gear, never make a general assumption.