"Ardour
While it may surprise you, Linux is building a reputation in the music world thanks to Ardour, a feature-packed Digital Audio Workstation (DAW). Ardour lets you record and play as many tracks as your hardware can handle, with non-destructive editing and countless effects. It does lack MIDI sequencing support (that's coming in version 3), but if you're happy to work with audio directly, or use an external sequencer, Ardour is a fantastic way to make music. Platform: Linux, Mac OS X
"Rawstudio
With the rise of digital SLR cameras, more and more people are using RAW format, and Rawstudio is the easiest way to handle these files under Linux. It lets you open RAW files and perform preliminary processing on them, such as colour management, white balancing, exposure correction, cropping, and straightening, all in full RAW fidelity, before exporting them to JPEG or PNG for further editing. It also supports batch processing, so you can perform corrections across sets of photos with ease."
