I've read some Lang's treatise, but I've always stopped short of trashing stuff that OS X brings along with it; there are all kinds of Asian fonts that I'd love to get rid of, but I don't want to find out what will break if I do (and they don't take up all that much space - relatively speaking - anyhow).
Back to your problem, though, I remember a similar problem with a much earlier incarnation of OS X, but damned if I can even begin to remember what the solution was... Anybody?