For fans of Reason, check this out-

http://www.rebirthmuseum.com/

I've been using this to make quick loops and so on.  Pretty cool and powerful for free.

Thanks for the link, Justin!!!  Awesome stuff.

VERY cool!

Check out some of the mods as well-

http://www.rebirthmuseum.com/downloads/mods.htm

Anokha, Omega, Regulator, Bone Vibes, and Circuitbreaker Theorem have some cool sounds.