My music wouldn’t be possible without a hefty collection of free software.

For recording and production the best option for me is Ardour.

For MIDI and connecting soft synths I find it easiest to use Rosegarden.

For mastering there’s nothing as good Jamin.

For a general purpose synthesizer I’m currently fiddling mostly with ZynAddSubFX, though I would prefer it to be more stable on occasion.

Last, but not least, I wouldn’t be able to run any of these without GNU/Linux. Distributions that I end up using are ArchLinux most of the time and Studio64 when something doesn’t work. Igno Molnar deserves an honorable mention for his wonderful RT kernel patches.