I've been using Reason for about 5 years now. I've made a lot of music in it, but the plastic sound of it allways annoyed me. I've tried Fruity Loops, and I don't know how the new version is, but the old thing was more a toy than a music program. I've tried Logic pro, but that just feels too cold and hard, and way too complex. Music should be fun! I've tried Arturia Storm, Buzz, that E-jay crap, all not what I wanted. But then... there was Ableton!!!
--== Ableton Live 4.4 ==--
Build for performing live, it is the best sequencer I have seen since Scream Tracker. I could write down a huge list of all the wonderfull features this program offers, but it's late and I got other things on my mind. But just check out some of the movies on the Ableton website and you'll see. This is the ultimate music program.