I want it . If I was to change anything it would be having only 1 hhd and 1 ssd

Get a 256GB SSD and a 3TB HDD. An SSD is far better than an HDD, and if you haven't experienced one yet, you'll never, ever want to go back to an HDD. If you seriously need more space for your operating system and files on the primary disk, get a 512GB SSD. Those cost around $150-$200, so only around $75 more than a 256GB. In my opinion, 128GB is too little for an SSD. I mean, I consider myself an average user when it comes to my SSD because all of my media, games, and downloads are on my HDD. I only have 70GB free of my 240GB SSD. If I didn't move downloads to the HDD, I'd be closer to 100% FULL. Imagine if you were an average user like me and you had a 128GB SSD. You'd probably be constantly moving stuff and it would be a hassle. As for the RAM, 2133MHz DDR4 is quite slow. Get AT LEAST 2400MHz, and preferably 2666MHz. Stay below CAS-15 though for an optimal combination of speed and cas latency.

I'd wait for new nvidia and amd gpus for a large budget like that, and you don't need 3 hdds

CPU: It's fine
MotherBoard: I've heard bad reviews about it so maybe go with Gaming 7
GPU: It's fine
HardDrive: 3 of them is too overkill
RAM: Go for 2400MHz RAM
PSU: It's fine
CPU Cooler: It's fine

Three HDD's seems over-kill, especially now that you can get SSD's. If you went for even a modest 128 GB SSD to load your most used stuff on, it'd be better than (roughly) the same amount of money for a 1 TB HDD.

A few things:

• I'd hold out on getting the GPUs unless you need this system now. Pascal is right around the corner.
• 2133MHz is slow for DDR4, and faster speeds aren't much more expensive. Corsair has some cheap 2666MHz memory.
• Are you getting an SSD? If you're picking up two GPUs and an i7, you should have money for an SSD.
• Did you pick the H100i or H110i? You said H100i but also said it was 280mm, which is the H110i's radiator size.

Holy xD