hardwood floor and speaker

I got a chuckle out of this one!

I use brass discs intended for use with spikes. They have an indentation in the center that the spike sits in, and allows you to slide it a little if you need to toe the speakers in or out. The discs are about the diameter of a quarter. They haven't scratched my flooring (hardwoods).

Audio Advisor sells 4 brass discs for $30.00/set. You will need 2 sets.

On my speaker stands with spikes I use 1/8" thick felt disks under the spikes. Works well and my hardwoods love me for it. I have oak floors so they are pretty soft.

I used pennies, then quaters.
When you move around your speakers to repostion, pennies or even quaters may not stick with the spikes, may end up scratching the hardwood floor.
Now I use speaker isolation cones. They are more expensive ($10~20), but they worth every quaters.

I am more interested in how people treat their hardwood floor surround the audio systems. Many times I see rugs (or some sort of office carpets) underneath the whole audio systems or inbetween the listening position and the speakers.
Would it be a good practice to put such rugs to dampen (or prevent reflection?) the sound from the speakers?