As an Artist and also a Software developer I have always Loved the idea of computer generated music. I was just wondering about all of the types that there are. I have written several myself in ruby..
That converts number patterns and Text into Music along with images etc..
Like to here what others use if anything...
There are a lot of options depending on what you want to do, how much you think/implement in code, and the level of complexity you're ready to opt into...the more complex, usually, the more control you have when you're tackling the tricky bits (talking to homebuilt MIDI devices, sensors, sonifying realtime data, etc.)
Here are some of the other packages you might want to check out.
cSound is a classic if you're not afraid of code. Max/MSP/Jitter is more graphical and insanely powerful. Pd (pure data) is an open source take on the Max/MSP paradigm. Reaktor is a more commercialized, easier-to-use, but maybe not-as-powerful modular synthesis/sequencing environment. U&I Software's famous Metasynth software can be sequenced with its companion product, Xx, for a very different kind of graphical computer music experience.
SuperCollider is a very interesting software which uses code to create sounds: http://en.wikipedia.org/wiki/SuperCollider
All the software mentioned by NoiseJokey is perfect for the purpose. I personally suggest Puredata. It's free and has a great community ready to help you with answers and patches. Maybe it's a little harsh at the beginning understanding how this software works... You could try Max/MSP. There's a one month working demo at Cycling74. It's the puredata rich cousin with a beautiful GUI and it's much more easy to learn, you have to pay for it...but you can use it with Ableton Live too (max4live). You'll find many videos of both sw on youtube.
