Best products for baffle material s ?

Thanks Zd & Rodman. I'll look into Corian.

Onhwy, there is absolutely no question that 'cabinet resonances', particularly those on the front baffle, reduce the clarity, dynamics and nuance of the sound due to the basic laws of physics.
I think ROCKPORT TECHNOLOGY website addresses this quite well. In a nutshell the drivers create sound by vibrating. For the sound to be 'just the sound created by the driver' there must be zero other vibrations influencing it. I understand your question as indeed different listeners have different "tastes" in both music and sound--so eliminating vibrations may not make the sound "better" to all; but definitely "different".

Daedulus, Rodman makes a valid and very interesting point. Serious woodworkers will know it "wood :-) " be virtually impossible for cabinets of different wood species to react the same to the drivers so they 'wood' all sound different!

"09-08-14: Onhwy61
I don't know the answer to this question, nor do I even have an opinion, but will the B&Ws sound better with a less resonant cabinet or will they just sound a little different?"
That's an excellent point. Whoever designed the speaker had to make it work with the original materials. Even if you go with a better material, there's no guarantee that it will sound better.

@Ptss- Some points about Corian; it can worked exactly as
wood(routed/dadoed/sawn/dove-tailed), but should be worked
somewhat slowly. Drills and taps nicely, for mounting drivers
with machine screws and/or clamps(obviating the need for T-
nuts). Dupont makes colored acrylic epoxies, specifically for
Corian, that can be used to layer sheets to whatever thickness
you desire, or to make visually seamless joints in a cabinet.
Unlike wood; it can also be thermoformed, if(for example) you
want to create a curved baffleboard. Versatile stuff!
(http://www.homedepot.com/c/BP_Corian)