Reason

Reason, created by Propellerhead, "is an integrated music recording and production studio with unlimited audio tracks, million-dollar mixing, and a massive collection of sounds included. Reason comes with all the instruments, effects and mixing tools you need for writing, recording, remixing and producing great-sounding tracks."

http://www.propellerheads.se/products/reason/

We imported a track created in Sibelius into Reason and the change in sound was amazing, the sound was full and real and did not sound that digital anymore.

Having played around a bit with the zillions of effects and knobs, I am sure that even the keen user will still find surprises after years of trying to master the program.

I liked the overview by MusicProGuides which Ed found on youtube:

http://edmund-kong-nmd201.blogspot.com.au/

or

http://www.youtube.com/watch?v=MPf6zkEGS14&feature=player_embedded#!

It's an 18 minute introduction.

There are also introductions and mini tutorials on the Reason website. The software is overwhelming and I felt like in a 'Malstrom' myself, but as they say, it is all about having fun and testing out the sounds. I changed a really boring tune I did in Sibelius into some gurgling spacey maelstrom.