How important is an audio rack?

If your gear is that prone to resonance and vibrations maybe your using the wrong gear.

Rhljazz:

Or, on the other hand, it could just all be marketing. Its seems like the people that say all these things are the very people that sell all these things.

Oh, how I long for the good days, before we knew about racks and wire and the doo hickies to hold the wire off the floor. Back in those days folks actually listened to music.

If your gear is that prone to resonance and vibrations maybe your using the wrong gear.
Gshepardbuster

Actually, it's the other way around. The higher the resolution of the component, the more likely you are to hear a difference. Not so much a problem for mass market and mid fi components.

Very few products at any price attempt to address internally generated harmonics or reduce externally transmitted vibration. Some CD players have sprung transports for example. There are amplifiers with floating circuit boards and Berning even uses Stillpoint devices in some of their amps to isolate the boards. Some of the casework on my VAC preamp is damped but it still is not immune to the stand or the room. All transformers create noise.

I generally find I like Stillpoints and spikes (although I don't buy into the vibration draining theory, whereby every resonance in the component is grounded through the spike)

Racks are expensive to try out, but maybe trying some of the footer tweaks would prove enlightening.

Rhljazz/Inna
The rack the salesman was raving about was from Box Furniture Co. I'm curious if your familiar with this rack?

No, I am not. Good racks are and should be expensive. I am not prepared to spend $800 or more on it, so as I said, I keep everything including the turntable on the floor. I think, quite a number of people here use Mapleshade racks with good results. Michael Green racks had a good reputation too but no longer made as far as I know.
When I tried Salamander and something else racks, they made such a mess especially at higher volume.