MusE is a multitrack virtual studio for Linux. It supports real-time editing of both MIDI and audio in an integrated environment. It has support for LADSPA and DSSI plugins (with Win VST support), JACK, and ALSA-MIDI output and input as well as internal softsynths. Numerous MIDI editors are available, including a piano roll, score editor, and drum editor.
There is full automation for both MIDI and audio.