REAPER is a professional Digital Audio Workstation (DAW).
If you're unfamiliar with the jargon, essentially this means that the program is a high-end and very configurable digital recording studio. You can import any audio or MIDI source, maybe plug in a microphone to record something, then loop, pitch shift, trim, time stretch, fade and otherwise edit your work until you're happy.
REAPER is able to map control surfaces (even game controllers) to faders, plug-in controls, REAPER actions and more, helping you to create a working environment that works just the way you expect.
Need more? The program supports all the major audio and MIDI plugin standards: VST, VSTi, DX, DXi, JS, and AU (the latter being OSX only), and so can be extended in just about any direction you like.
And all this comes at a surprisingly reasonable price, for the DAW market at least: if you're happy with the trial version then REAPER can be yours from $60. See the REAPER site for more.
Version 4.77 changes:
• JSFX: ? fixed last touched parameter when skipping sliders .
? support for naming sliderXY variables via @sliderx:varname=defval<... syntax
• Media explorer: ? support for MIDI/OSC action binding
? fixed potential crash with bad timestamps .
• MIDI: ? fixed encoding of linear tempo changes in exported MIDI
? .mid file writing fixed when ticks per QN is configured higher than 64k
• Screensets: ? better project tab support for FX
? fixed screenset issues with input FX and hardware FX
• Assorted other fixes