Well, after much debate with myself, I finally settled on using 7/16″ OSB sheathing for my walls.  Normally I wouldn’t have considered it, but my local Lowes had some that was really cheap.  Same price as drywall and one side was kinda smooth, like they had applied extra pressure on that side or something.  It’s still got a heavy texture, which I think will help deaden some sound.

I canned my original plan to use accoustic ceiling tiles.  I checked them out and they were just too fragile.  With the OSB, I get a good strong wall that I can easily hang stuff on.  I’m planning to spray it with Kilz2 latext primer and make it bright white.