MusE v0.9pre3 (Linux/Free)

Excerpt from the ChangeLog:
* Fixed bug 1650953 - select and move segfault
* Fixed broken master list editor. Should cure bug 1687166
* Added auto part resizing to drum canvas
* Fixed intermittent crash when cutting a part.
* Fixed arranger part selection
* Fixed arranger part operations (move etc.) to use selected part.
* Fixed arranger keyboard left and right previous/next part selection.
* Fixed wave editor - Black selection bar intermittent drawing.
* Wave editor now allows you to open multiple selected wave parts
* Fixed intermittent arithmetic exception crash in wave viewer.
* Fixed bad wave drawing above certain zoom level in wave editor.
* fix for sustain pedal to work as suspected when looping.
* Feature request: 1650957 space bar should start/stop playback fixed
* Fixed bug 1645575 - Eraser tool causes segfault in drum editor
* Fix for bug #1074808 "NRPN - still 128 values?"

MusE is a MIDI/Audio sequencer with recording and editing capabilities written by Werner Schweer. MusE aims to be a complete multitrack virtual studio for Linux, it is published under the GNU General Public License. MusE has among other things support for:

* Midi sequencing
o Record/Playback/Import
o Input filter
* Audio sequencing
o Record/Playback several mono/stereo inputs/outputs.
o Use effects
o Nice routing features
o AudioGroups
o Perform audio effects like chorus/flanger!
* Jack
o Use the Jack Audio Connection Kit for midi/audio routing.
o Internal Audio Routing Interface
* ALSA - based on the Advanced Linux Sound Architecture

You can use several soundcards to access external midi devices and record/playback them with MusE.
But MusE is much more.

MusE is a multitrack virtual studio for Linux that has support for sequencing of both midi and audio and has, among other things, support for LADSPA, Jack and ALSA.
Read more here.