Disclaimer: I don't compose music, but a friend of mine does, and there are some things that made a big differece to their performance.
At this point, I would advise against going with an AMD CPU. DAWs can be rather CPU intensive, so I'd rather wait and see if AMD's Zen core will be any good, and if not, go with an i5/i7.
I would also recommend 16GB of RAM for your workload - DDR3, not SODIMM.
That GPU won't really be suitable for any sort of more modern gaming, though it would probably be ok for 2D and less graphically intensive 3D games (think CounterStrike: Source, maybe GO). If you're not gaming, it will be fine.
I also can't stress enough the benefit of an SSD - makes things soooo much faster.
Pretty much all computer monitors worth talking about have a good response time, so I'm not too sure what you're looking for there.
Of course, this is all dependant on your budget, which you're yet to disclose!