I've heard good things about Ardour http://ardour.org/ http://ardour.org/ especially and also Renoise http://www.renoise.com/ http://www.renoise.com/ but I have

I've heard good things about Ardour http://ardour.org/ http://ardour.org/ especially and also Renoise http://www.renoise.com/ http://www.renoise.com/ but I haven't tried them personally.