alternatives to spikes on wood floors?

To make leveling with spikes possible without puncturing the wood floor, I chamfered eight pennies in their centers with a quarter inch drill bit and put these under my spikes. Cheap and easy!

The spikes may not be needed at all. I once had my Thiels on hardwood - made no significant difference with or without the spikes (I spiked them on thick ceramic tile) in my room. The purpose of the spikes for Thiels, IMO, is more to couple the speakers to the floor over carpeting than vibration control. The Thiels are very very solid, so I don't think vibration is as big of an issue with them. In my opinion, I don't necessarily agree with "... I know I should be using them up on the spikes ...". Of course, your situation is most likely different than mine - my speakers are placed where the side and rear walls are not a significant factor.

Polycrystal makes a product called "cone-coasters." You can read about this on their website. I had the same problem you had. Cone-Coasters solved it.

http://www.audiopoints.com has brass coupling disks.

thanks to all so far. again, this is why i love this site. i'll consider your recommendations (the penny solution is definitely the most creative). As for whether "i should be using the spikes" i appreciate your take GS5556. I found that there was a noticiable difference when i put my old 3.6s up on spikes so i was just assuming the same would hold for the 6s. Unfortunately, i am limited in terms of speaker placement (they are close to a wall behind them and not far from walls on either side). Perhaps in this situation getting the speakers up on the spikes seemed to open up the sound (at least they did for the 3.6s) and provided a cleaner, less muddy bass).

anyway, thanks again for everyone's help.