How thick should the front baffle of speakers be?

The woofer should move, but no other part of the speaker! :) I think that it matters to some degree. A woofer exerts tremendous force on the cabinet. Any flexing in the front baffle could lead to Doppler-like effects as well as additional, unintended sound sources. The ideal speaker's output is ONLY from the drivers. This is different than a musical instrument where the strings or membrane AND the body resonate together.

MDF is cheap though. :)

Best,

E

So I shouldn't be able to put my martini shaker on top of the speaker and wait 10 minutes to sip?   :  ) 

+1 Erik
That makes good sense since eliminating micro vibrations to the cabinet through footers etc. greatly increases speaker presentation. I never knew what mine were capable of until I put them on ceramic ball type feet.