vibration control

Paperw8,
I think that what is ridiculous is making the comments you make without having tried any of these devices. It isn't always possible to explain why something works, but that doesn't mean that it doesn't work. That isn't to say that there isn't good science behind some of these devices.
Anyway, why don't you give it a try? You may have a pleasant surprise.

i don't get it with all these "vibration control" devices: is the idea that they prevent the vibrations from shaking up the electrons, which would (presumably) affect the sound? the idea of it all just sounds ridiculous to me. but many of these "tweaks" sound ridiculous to me. the only component in which i can see a legitimate need for vibration control is a turntable.

If you don't want to drill too deep, a good place to start is by making sure you have solid, non-ringing support for your gear, and then trying Herbies products (start with the simple isolation feet );
http://herbiesaudiolab.net/

TMC air isolation platforms under all. Tube line stage,Tube CD player, DVD player, SS Phono, Basis TT, and both A/C regenerators.

Yes SYMPOSIUM Ultra,Rollerblocks etc the BEST by far..

I use some form of vibration control or tuning under just about every piece of equipment. ( Many times people use the term "vibration control" when the item in question actually just varies resonant frequencies.) As Roxy54 says, they all sound different. Plus, every piece of equipment is different as far as how much vibration control or tuning affects it. My Marantz Sa11S1 is greatly improved by the Boston Audio xl tuneblocks I use, but they make only a slight improvement under my other gear. I also use three maple plinths, one under my turntable, phono stage gain stage, and phono stage power section.

Useful yes but most of the time way over done...just my take.

It is useful to use isolation devices under every component. There are countless types, they all sound different, and you will definately have to experiment to decide what works for you. Start with cheap things like small myrtle wood blocks. There are so many good things. The brass cones by Mapleshade are also very good.