This is my personal favorite, and the D.A.W. I use almost all of the time. It can be a bit hard to step into, but if you, as most others, started out with Fruityloops it shouldn't be to big of a problem. Ableton Live's live mixing capabilities are especially good. So check this out.
My old D.A.W. Hard to get used to, but once you get the hang of it, it's a powerhouse. If you really want to be able to do a lot, but you also know how, then this should be your choice.
If you want usability and something you can easily pick up and start making music, Reason ought to be your choice. It's interface is easy to understand and it's synthesizers and other plug-ins are easy to use. This is how I began making music, perfect for beginners.