Your original build is pretty solid.
I'd echo that 8Gb of ram is basically a no-brainer. It's not super expensive, and it's good to have.
The size of your monitor is irrelevant, the display resolution is not. If you are using a 50inch 1080P display it's identical to a 20inch 1080P display in terms of it's hardware demands. If you are using a 1080P screen, then Nickeroo has a pretty valid point in that you can save some funds here, even low end cards are remarkably 1080P capable these days. Something in the GTX770/R9 280X range is probably about as much sense as it makes to spend, and even those are fairly poor value/performance at that resolution.
The Antec case seems ok, but only if you want to use the slim ODD. Otherwise I'd probably be drawn to the (more expensive, but not vastly more so) Fractal Design Node 304. It has better general airflow, a built in fan controller, and fully vented sides which support an axial fan graphics card (like the one you chose) much better.
There is also the Coolermaster Elite 130 which is pretty excellent value.
I'd also upgrade the quality of the PSU. Corsair CX are entry level. Your build is not.
There's a lot of good PSUs on the market, but I can't see any Corsair's I'd buy right now as they just aren't falling into the right pricing versus the competition. The Antec HCG-620M has been on discount on and off for months and it's great quality, semi-modular, and not really any more expensive than the Corsair.