If you have the money, I sincerely suggest FLStudio. It's extensive and complex compared to most, but it also has more features (of which are beyond flexible) than most brains could ever wrap their minds around in years. This, mixed with a midi out interface, to an electric keyboard basically gives you a full-on, in-home studio, providing more features than many actual studios provide. However, to push FLStudio beyond 'Reason' in terms of quality/latency you definitely want ASIO4ALL v2 drivers.
If you're looking to turn music into a long-term hobby, or job, then investing money is always the way to go to embed yourself into the mainstream of things.
Good luck