Man, I wish I had seen this write-up three or four years ago before I started working on my basement:

http://www.ethanwiner.com/acoustics.html

Thanks to my co-worker Tim for pointing me to it. In reality, I probably wouldn't have changed very much in my music room design in my basement even if I had read it before. But what I'm most concerned about in my music room are the parallel walls and how they'll cause a lot of unwanted sound reflection. While this article talks about how to construct your room to avoid those things, it also talks about how to eliminate them in a room that has unwanted reflection. So I think I'm covered, if I have the problem :)

Tim also pointed me to a recording studio design forum. In there is a post by a guy where he describes how he constructed some bass trap panels (see included picture). The panel design is taken from the acoustics article above.

One thing I've read in a number of places is the importance of a hard-surfaced floor in your studio. I'd been playing around with the idea of using hard-wood floors in that room, and now that idea is solidified. Originally I was going to go with carpet, but it sounds like carpet will do nothing but make the room sound dull and boomy. A hard floor with attention to deflecting and absorbing sound on the walls and ceiling is a better design. So on that note I can't wait to build some panels and try positioning them on the walls and hanging them from the ceiling. Oh, wait, I need to actually finish the basement first.