Browsing Freshmeat tonight, the premier online Linux software repository, I came across to these two great (and brand new) applications,
ReBorn and
ReZound. Reborn, a Rebirth clone that will soon become open source according to the developer, provides a software emulation of three of Roland's most famous electronic musical instruments. It got me thinking as to how much more viable Linux is today as a professional (or semi-professional) audio platform than it used to be two years ago.
Update: On a related multimedia notice,
WinAMP 3.0 for Windows was released yesterday.
A lesser known, but truly professional sound creation and manipulation tool is Cecilia - http://www.musique.umontreal.ca/electro/CEC/. It provides a GUI for CSound but goes much much farther than that.
It is suited equally well for "scientific" sound engineering and for Aphex-Twin style mutilations of sampled sound.