New customer - 2500$ gaming rig please help

Budget:
[2500]

Expectations:
[Able to last at 5-6 years without needing to swap out parts, understand will have to lower some graphics settings. Problem free for 5-6 years]

Usage:
[Mostly gaming + web browsing + streaming]

Special Needs:
[Must boot/load really fast, play starcraft , dota, doom, Arkham knight, and other future games at ultra no problems]

Saved Ticket #: [] 1445143

Specifications:
[Want to ensure great temps are achieved. Computer is located under the desk. Currently using a Dell 2312 for gaming and an AOC 19 inch plug in on the side for a dual monitor set up, but gaming is only on the Dell. I plan on getting 2x U2415 to replace the 2 monitors i have, but that's the most ill go]



Hello there, this is stargaze - been a lurker for a little while, finally making my first post! Please bear with me because I have a lot of questions for you guys!

I've chosen the Apollo because it's more of a vanilla/all around case but I do have some follow up questions:

1. Case - My lurking research is telling me that if i go with Corsair AIO 280mm fan cooling, the fans will be installed at the top of the apollo case - which means the top will be constantly exposed and dust will collect. Is this true and is this a big concern that I should have? But if i go with a Noctua fan that means the top will be sealed/covered and there are no side panel fans on the Apollo. Would airflow be worse now? Fearing that - that's why i chose the AIO for now but I do want to hear opinions

2. Case again - I was going to choose the Coridium but I was worried that smaller case = less airflow which would be bad for temps and especially with 104 degrees hot summer and I'll be putting the case on the ground under the desk may cause further heating issue. And from what I can tell Apollo has 4 usb ports on the front of the computer vs 2 on the coridium so i guess more USB ports the better, that's also why i chose the Apollo. Am i making the right judgement here? Also, not sure if noctua in the coridium will be barely enough room , hence less airflow again.

I have also read from a post from before that if i use corridum i can ask DS to carve out space and add fans to the side panel. But is this better than Apollo with a noctua/280mm?



3. SSD - I want a larger size SSD from the 120gb I have now, but I am not sure if there is any justification to get the 512gb PRO. What about the SSD M.2 (512GB Samsung 950 PRO)? is there even a remote justification for this for $200 more?

4. Is 850w enough?

I'm sure I have more questions but thanks for taking a look at this first!

@ stargaze - I have a similar build as yours actually. I'm thinking of getting 280mm so the radiator fan will be @ the top of the case. I'll gamble with the heat output + noise.