An 850w PSU maybe overkill for a single GPU setup, but PSU hit their peak efficency at 50% Load. And you'll have that head room if you want to go dual GPU one day.
The Noctua NH-D14 is huge. Xigmatek Dark Knight Hawk (which I've been recommending alot) won't block your ram slots and does a really good job of cooling. And is probably cheaper than the Noctua.
The Antec 902 is a really awesome looking case. I have one. BUT..............
This is a big BUT (and don't think dirty)
It's narrow, you will find yourself spending an insane amount of time with cable routing to get the cables sitting nice and flat between the motherboard tray and side panel.
It's short and difficult to work with when installing motherboards with big heatsinks.
It's also short in depth so long GPU's are more difficult to fit, particularly with after market coolers such as the Arctic Accelero Extreme.
The HDD cages are another pittfall to this case.
Firstly each HDD requires 4 screws to mount.
Secondly each HDD cage has 8 thumbscrews. You'll have to remove 16 thumbscrews just to clean 2 dust filters.
As good as this case looks and probably Antec's most aesthetically pleasing design it's a time consuming build. And trust me you will get sick of thumb screws.
This is my old build. Note how close the Heatsink is to the top and the GPU cooler is slightly in between the 2 HDD cages I had to move one up 2 slots.
Go for a full tower case you won't regret it.
My old build with new GPU and case Coolermaster Storm Trooper. Much better spacing.
Upgraded but no more H100i due to a small electrical problem that melted the plugs. Them's the breaks.