How important is the rack you use for your components

I agree that a good rack is important and will influence the sound of your music. I'll also add that physical appearance is also important to me. I'm not going to buy a rack that has an excellent sonic ability with what is placed upon it unless it is physically appealing to me.
There are many very good racks available that look and sound good, luckily I own three that are made by different manufacturers.
I agree with mgattmch and his comment regarding the Core Audio PlyCraft 3L rack. I received mine about 10 days ago and as already mentioned it is incredibly well built, beautiful to look at and incredible acoustic isolation between my amp, transport, and Dac.

@randy-11 -- nice, but requires a pump and air supply to operate. Also I worry that they require a fairly hefty minimum load. 

I’ve always used simple steel racks to good effect. My turntable is on a Sound Organisation 3 tier rack; I’ve owned that rack since the early 90’s and have been happy with it. My other gear sits on SolidSteel racks. I’m satisfied with those too. My point is buy something solid and well made, which need not cost as much as an amplifier. Are my racks beautiful? Not really, but highly functional.

I haven’t played with different racks, as aesthetics dictate a console between my speakers. With the console, though, I’ve noticed putting spikes under the feet helped improve imaging and bass response. As did isolating all my components using springs. I put my turntable and tube pre on wooden platforms, which are then placed on springs. My oppo is isolated with springs directly under the chassis and my amps sit on top of the oppo. With more space, I’d suspend the amps on their own shelf. But alas..

That was a very long way of saying I’ve noticed changes/improvements when messing with my rack. I can only imagine a dedicated rack would bring even more sonic differences to the table