I enjoyed this article on Rosegarden as it approaches v1.0.

Rosegarden is a fully featured audio and music sequencing and score authoring package for Linux. I had high hopes for it a couple of years ago, but at the time, I couldn't get it to stay up for more than a minute or so. A poor experience with music on Linux in general was the final kicker that made me a Mac person. With newer Linux distros and Rosegarden reaching 1.0, I wonder if I'll regret having spent big bucks on commercial solutions. (Would I ever install Linux on my Powerbook? !!!)