Suggested power for a rock band laser show

[Dervacumen]

I'm about to undertake a simple laser project that will be used at small venues by a band.  At certain times during the show we will fog the area about 10' -12' from the ground (normal ceiling height) and then use a laser to project a 2D flat plane in to the smoke, giving the illusion of a ceiling.  I'll accomplish this by shooting a laser at a spinning, mirrored octagon.  I imagine 5mW, which is the standard laser pointer wattage is too low powered to reach very far.  Since the lasers will be well above anyone's head there won't be a risk of hitting anyone in the eye.  Any suggestions on laser power?  100mW seems like overkill.  Maybe 50mW?  Or even 25mW?  On the other hand, as long as I have fog the 5mW should be not only sufficient, but safe.
Thoughts?

[Le Chuck]

Although lower powered lasers are less a risk they are by no means eye safe. If you have all the safeguards in place to prevent direct exposure then 100s will give you a very bright show. That said the lower powered units will likely look just as good. What's the price deferential?

[ChadTower]

Also keep in mind you can take some shortcuts like light smoke from a machine.  That'll show off the lower power beams much better.

[Thenasty]

alot of the LASER LIGHT for DJ like American DJ or Chauvet uses 10mw laser diodes.

here:

[Dervacumen]

I've seen 100mW green lasers for $50.  I've also seen boxes with a green 100mw and red 50w for $35.

The galaxian sky video shows basically what I'm putting together.  10mW looks good as long as there is fog - which there should be in most instances.  I was leaning toward 25mW, but since I can get a box with higher powered lasers for less $ I'll probably go that router.  Then I can rob the box of the lasers and build my own setup.