If you want to see data CDs, but are sick of the uninformative "Audio CD" icon and name wasting space, simply use the SetFile tool (see this hint). In the terminal, type:
sudo SetFile -a V /Volumes/"Audio CD"/Now, any and all audio cd's will be invisible... but everything else, assuming you haven't named it "Audio CD", will appear.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011102001005247