Well said Mr Fletch. I think they all have their own advantages and disadvantages. The one that stands out for me is reason for a beginner. Simply because it mimics real life rack equipment and CV routing... all essential when starting to piece your studio together. I like Ableton but trying to get your head around warping from the start can be a little difficult. "the hours I've spent chopping up little breaks and waiting half an hour for the sampler to load... now you can just warp!" conversation wears a little thin after a while.
On the controller side... get down the local studio shop or a local exhibition and try a few out. Akai and Novation would be recommendations of mine.
hi - before you start throwing money at your studio - i deffinately would recommend what the guys above have been saying.
try out the software - you can also download keyboard emulators ( i think one is called Bome keyboard emulator) so you dont have to purchase one straight away
once youve had a try of the different software out there then make your decision.
There is no answer to your question - it all depends on what you like and/or can afford.