Do you use spikes for tile/marbel floor?

I'd recommend a faily inexpensive tweak. You can use cones under the speakers that you can buy through Audiolabhawaii.com. These cones increased the dynamics and bass of my speakers. I've used many different cones and these are the best.

Elb I never heard any objections to that approach; it makes sense to me. I believe that should work just fine; you're basically piercing the carpeting with the spikes & all the weight atop of them is bearing directly onto concrete.
I wonder who says that this won't work & what was the reasoning? I'd tend to disagree, although maybe I'm missing something?

What about using spikes on a regular wall to wall carpeted cement floor? That's what I do. Is this a good thing? I have heard that it is and that it isn't.

If you have the option flip your spikes over and put the rounded end on the floor. This has worked well on my pergo and slate floors.

Replace the spikes with Black Diamond Racing Cones. The BDR cones will not harm your floor and will allow your speakers to reach their full potential.

I prefer to use a brass coupling disk that can be found at: audiopoints.com mine have worked great on hard wood floors, concrete, and the bottom side of my stereo components where the point of a spike meets the bottom of the equipment.

It depends. My Martin Logans prefer brass spikes into brass cups and my Thiels prefer thin nylon washers.

I have my spikes replaced with standard furniture glides from the hardware store. Meadowlark recommends this for their Kestrals, might work with your speakers as well. The thread size is common, 1/4 20. If this doesn't work Linn makes a product called "Skeets", hard metal discs with holes in the center for spikes. Hope this helps.

4 pennies per speaker. This is the way to go.
Cheap and doesn't muck up the hardwood floor.

I'm using Symposium Svelte speaker platforms under my Hales T8's. They are on tile and do a great job of coupling the speaker to the floor.

I have hard tile over concrete flooring, with the BBC MK-2 gold plated brass cones (available from May Audio Marketing) which come in nice boxed sets including the little saucer protectors for the floor. These have a nice low profile & even have threaded adjusters with locking nuts so you can snug them down tight even on somewhat uneven surfaces. They claim that the protecton saucers actually enhance coupling vs. degrading it. The cost is quite reasonable & the sonic improvement is indeed significant.
I've heard of coins being used as floor protectors but the spike eventually drills its way right through. Vibrapods have also been reported to work well under speakers although the sonic signature surely must be much different than with spikes; it might be worthwhile comparing.

I am confident in believing that you should get some intermediate device. You would be a little hard pressed to find a speaker that would sound as good riding bareback on any type of floor. I have used audiopoint spikes and disks on hardwood floor and found that combination to work better than a spike/carpet combo, and much better than simply resting the speaker on the bare floor. Some have found good sonic results with Vibrapods as a replacement for spikes. They can be used alone without causing damage to your floor.

I use an extra tile or two with teflon gliders glued to them and spikes sit on top of that instead of directly to the floor. I use the spike cups also that hold the spike in place and keeps the speaker from sliding and also helps to absorb vibrations along woth the teflon rubber gliders underneath the extra tile . The teflon helps when you want to move the speaker to make adjustments - you do not have to take it off the extra tile. This helps to keep the existing floor from being scratched or dented by heavy speakers with spikes.

Speaker spikes are almost always beneficial. The problem with tile or other hard surfaces is the damage the spike can do. The weight of heavy speakers, combined with their energy transmission during music sessions can literally "drill" a spot in your floor.

Sound Anchors makes stainless steel discs that employ Kevlar on the back side. Not only can these disks not be penetrated by any spike, the Kevlar does not store energy when working against rock hard surfaces such as you have.

I plan to use the Sound Anchors on my new floor, I have slate, which is hard but certainly vulnerable to the stainless steel spikes I use. For what it is worth, the Sound Anchor product was a Stereophile best buy recommended product. I think it is better to buy a few and listen first though, rather than follow only my suggestion or the magazine.