alternative to speaker stand spikes?

You can still use the spikes and protect your wood floors with ConeCoasters made by Sound Anchors (the guys who make speaker stands for B&W, etc.).

The coasters work great.

I am using Aurios [set of FOUR, for stability] under my speakers.

If you are cheap like me, try a nickel. If you are a big spender, you can use quarters. You can also paint them and put stick on furniture glides on the bottom which will allow you to slide the speakers slightly should you need to.

Another good alternative are spike footers. audio advisor is 1 source.

Another inexpensive alternative is to take one of your spikes to the local hardware store and purchase hex bolts or carriage type bolts with same thread dimensions. You can then attach a protective pad if desired. These can be securely fastened to the speakers with the provided nuts. If nuts aren't provided you can purchase them at hardware store. Total cost should be less than $10.
This has worked well for me and my wood floors. I've suggested this several times and am curious if anyone has tried it.