Well, there's many alternatives, you've got the ones already mentioned, FL studio and Ableton live, but there are many others out there. Off the top of my head: Cubase, Logic(for mac), Reason(more of a rack emulator, but can be used for some wicked ominous backdrops), even something as simple as Audacity could be used if you have some real life instruments that you're decently good at, you know, the list goes on. With the exception of audacity, all of these cost money tho, so be prepared to dish out some cash. Hope I helped