Looks like a great pc. should perform amazingly in what you want it to do.
is kind of overkill for 1080P gaming but perfect for 1440P gaming on ultra.
If you have no plans to overclock and run multi graphics cards (psu couldnt support more then 1 anyway), you could save money by not getting a K model cpu, and getting a cheaper motherboard.
the keyboard/mouse you are getting are absolute trash. They are your average $8-10 keyboard and $10 mouse, but they added LEDs to them to make them shiny and "gaming".
Any old $10-15 keyboard is fine (mechanical keyboard are very nice and very rugged, so they will last longer), but you should think of getting a good decent gaming mouse. Id recommend something in the $35-80 price range where all good gaming mice are at. You can get something cheaper like the logitech G402 or something and thats a great mouse. (i have a G502, its almost the same mouse). corsair also make some good gaming mice, and roccat do too. (i dont recommend razer).
that headset is ****. for the price there is MUCH better. "7.1ch" is a gimmick. you only have 2 ears, and you are placing the headphones right on top of them, there is no such thing as "surround sound" in a headset...
"surround sound" was originally made to be just that. sound that comes from all directions. when you wear headphones, this already happens. your brain is actually pretty amazing, and based on the sound, your brain will tell you where that sound came from and how far away it is compared to other sounds.
[google "virtual barber shop". its like a 10 year old video (yeah...), and abiet low quality, gives you a very good example of how your brain works with sound, and that when playing games and watching movies, they all do this exact same thing to give you the positional data of things so that your brain can tell things like position and distance. modern technology just far improves on this concept]
since you are buying a separate mic, jsut buy headphones not a headset, since most headsets are terrible. the decent ones start at $150+ (like sennheiser pc350), but you can still get a better pair of headphones for $100, and your mic is already better then the mic in a $150 or under headset.