On the subject of goodies for Linux, I've just ran across a
direct-to-disk recording system for
Linux called SLab. It supports mixing, EQ, effects,  etc., an API for
plugging in your own effects,
and has a very slick interface.  It's written in a combination of tcl/tk
and C.  While I haven't had a
chance to use it deeply, if it works as well as it looks, it is a "must
have"  for anyone using Linux for
music. See:

ftp://sunsite.unc.edu/pub/Linux/apps/sound/mixers/SLab-1.0.tgz

Tomy