Where to use Isolation devices

I use devices under everything and believe everything seems to benefit, including speakers. I use a range and don't believe myself, you need to use the same throughout.
Herbies products are always good value, I use the Isocups. I also have some Stillpoints and Black Ravioli, a UK product. Both are excellent and better than the Isocups, but a lot more expensive, even second hand. I have used or tried some brands I did'nt like, particularly HRS. In my system, they did'nt have much impact.
I am sure the way to go is to look out for second hand products on the Gon or other sites and just try them out.

The type of isolation/coupling to use, and where, and the "amount" of such is a matter of tuning (trial and error). I have never found it to be the case that more is necessarily better. It is possible to end up with a dry, sterile and harmonically bleached sound with too much of what is supposedly a good thing.

I have generally found the biggest effect to be under speakers. Often, the most commonly used device, the pointed spike (really a coupler, not an isolation device), is NOT the right approach over something like a suspended wood floor. In those instances, a platform with a foam type core to absorbs vibration is better than coupling through spikes (e.g., a Symposium Svelte shelf).

After speakers, I would address source components like turntables and CD players. These are sensitive components, but again, sometimes additional isolation is not what a system needs so it is a case of trying different things. I once helped with a trial of different shelves/devices under an Aero Capitole CD player that sounded surprisingly much worse with almost anything under it that is suppose to help with supression of vibration. The designer must have tuned his component for just what was needed (it came with something like Black Diamond cones for feet). My own CD player is somewhat immune to treatment--it doesn't sound that much different with special shelves, rollerblocks, etc.

In short, every system and component is different, so no single magic bullet works in all cases.

I would put everything on Audiopoints to begin with and see what happens. Personally, I use various devices under everything: Audiopoints, Polycrystal footers and speaker spikes, Boston Audio tuneblocks, Mapleshade isoblocks and some inexpensive German steel cones.

Some good responses, thanks. The latest isolation device I was able to try recently was the Nordost Sort Kones. The shop I went to said that he would be money on the fact that I could hear the difference between a cd player without anything, and then with the Sort Kones....well he was right. I heard a lot of difference with the Sort Kones in regards to inner detail, more decay with the cymbals and drums, and I guess a little more air around everything. They are cheap at 60$...I am going to get three for my cd player to start out with.

Sean34, the Sort Kones are actually a coupling device that is in fact the opposite of an isolation device. The coupling devices, in theory, provide a path for any vibration to leave the equipment while isolation devices should isolate the component from the surrounding environment. Having said that, they are used for the same purpose. I have three sort kones and believe that I hear a difference as well.

I wish I had two identical CD players that I could setup identically for an A/B test that didn't involve the delay of installing and removing them.

I think an idea setup just might be a chunk of marble or other heavy inert platform that is sitting on isolation devices with the component on coupling devices on top. Should be the best of both worlds, in theory.