>>Do you think it helps pin the speakers to the floor?
No only people.

>>Do you use them only on hardwood floors or do some of you use them on carpeted concrete slabs?
Depends on the mosh pit.

>>What other floors would you use spikes for?
See above.

>>How about other accessories?
Not really into body piercings, but different colored hair can be cool.

>>Do you use risers for your cables?
No only people or speakers.

>>Alternative stuffing for your speakers?
Haven't used animals or dead people yet, but heard animals can be used for room treatment if you have enough of them.

>>What kinds of things like this do you think really work, and what ones do you think are nonsense?
All of the above.

Sorry couldn't help it :^)
Bill W.