Agreed re the extra cores, I bought the new Broadwell E stuff with extra cores last year (6850, 6800, and a 6900). Unless you're doing some really specific applications like say video encoding, or other stuff I never do, there is NO point at this time the way the vast majority of games are created. My 6700k performs virtually identically, even better here and there, than a CPU that cost many times that with the 1080/ti/Titan. The 7700k is still the best selling single CPU right now according to Amazon and other trackers in the gaming market, and that's for a good reason. If I was building a gamine machine right now, something very close to the OP system is exactly what I'd do - good job Bow, nice upgrade.
Regarding a 1440p monitor - what kind of $ are you looking to drop? IMO a high hz count, 144hz, 165, even 100 for the larger 34"+ panels, is the best "gaming" feature you can have in a monitor right now. Resolution comes next, tied with the type of panel, ie TN, IPS, TA, etc, then size, then Gsync. If you can swing some $, a monitor that has all the above will serve you well, such as a 27" IPS 144/165hz Gsync can be found for 5 or 6ish USD if you give up some features, and $700 to $800 USD will probably get you any of them from Acer, Asus, Viewsonic, AOC, etc. I personally wouldn't recommend getting a 1440p monitor that only does 60hz, for me I'd rather use a 144hz at 1080p if I had to make that call, but again, getting both is possible with some dollars.
If you give up Gsync, something like this will have 144hz and 1440p in TN panel type for $400 ish if you look around -
https://www.newegg.com/Product/Product.aspx?Item=N82E16824160297For $800 you can get it all, IPS panel, Gsync, 1440p, 165hz, 27" -
https://www.newegg.com/Product/Product.aspx?Item=N82E16824106004There are lots of options in the middle from the major manufacturers, giving and taking various options. I got rid of our 34" Asus 100hz 1440p, but still use the ROG Swift 27" in both TA and IPS screen types, 144 and 165hz capable both with Gsync. Excellent monitors. Even with the Rift and Vive, I still find I use a gaming monitor for many games out there, so I'll be grabbing the new 27" 4k 144hz Gsync that is coming from Asus and Acer in 2018, but that might be the last monitor(s) I buy, as I expect higher res VR will be out before anything better than a 4k 144hz monitor comes out.
