And Rosegarden is one of the most comprehensive music composing programs I’ve ever played with. LMMS is another choice for a composer as well as a mixer. Audacity is an excellent and versatile audio recording and manipulation tool.

The only small hurdle is that many default kernels in popular distributions don’t compile the RTC (real-time clock) component out of the box and so you will get many warnings from audio applications about the system timer resolution being too low. This is not a critical error, but might frighten many new users.