$1500 gaming pc, first build

I would go with an ATX case. (Mid size tower) ATX is a standard size for the majority of motherboards. Mini ITX boards are less prevalent and may limit your options. Mine is the Antec 300 and I love it. The price for the Antec 300 would save you about $40 - $50.

Also, bump up the power supply to 600W. At that level you can add pretty much any single video card you want, even the big power hungry ones. Personally I'm a fan of "PC Power and Cooling" and Antec power supplies. Also, the one you chose is an ATX size power supply and may not fit into the mini ITX case you chose.

The liquid cooler you chose really isn't that great. Big air cooling is often better and cheaper than liquid cooling unless it's a fairly large liquid cooling system then liquid cooling is king. But the bigger liquid cooling systems are typically much more expensive. The Cooler Master Hyper 212 Plus is fairly cheap and would do a better job. Typically big air cooling is defined by tower coolers with 120mm fans or bigger. To get that kind of cooling from a liquid cooling system the cost can get kinda high, so personally I stick with airflow. Which for my case 2x 120mm fans on the front, 1x 120mm fan on the side (near the video card, 1x 120mm fan in the back (included with the Antec 300) and 1x 140mm fan on the top (included with the Antec 300) means lots of airflow and no temp issues even when highly overclocked.

Spend more and get two sticks of that memory because then it will run in dual channel mode. (much faster)

If you absolutely must keep the mini ITX size then just make sure that power supply will fit. Also that video card might be too big to fit as well. Do the dual channel memory regardless of what you decide.

The rest is fine but I would save money by getting a Core i5 instead... The i7 doesn't offer much of an advantage unless you consider a higher price an advantage! LOL Take a look at the article here on Tomshardware.com that comes out monthly called "Best Gaming CPU's for the Money". Go ahead and trust their recommendations depending on how much you want to spend.