SSD = Samsung EVO (OS/Apps/Scratch Drive)
Prefer the Pro drives for work-related stuff (big on warranty coverage). But the Evos have proven damnably durable.
HDD = Western Digital Gold
These are not standard commodity-grade drives. 2.5x time Mean Time Between Failures interval and better numbers (by a factor of 10) on Unrecoverable Read Errors (important in RAID setups).
Motherboard
I've been an Asus guy for a while due to stability. But their product and warranty support can be asstastic at times.
Used to love ABit enthusiast boards.
And will be going ASRock (a corporate cousin of Asus through Pegatron) for my new build. Their current last few generations of boards have been solid, stable performers. And I actually like an engineering decision they've made.
Some boards, if running more than one NVMe drive, shuts down 2 SATA controllers for every drive after the first.
ASRock is different. Instead of shutting off storage options, they opt to disable the third (technically PCIe5) slot to scrounge the I/O.
Seeing as multi-GPU solutions are going by the wayside, this will generally affect fewer people.
CPU
Agreed about best CPU you can get for the money.
As for liquid cooling, I've had a 280mm All-In-One in my main machine for about 6 years now. Still going, haven't sprung a leak. Nice, solid, dependable.
Now, custom loops and stuff, for that, you're kinda on your own.
RAM
I've had good luck with G.Skill and Crucial/Micron and Kingston. I've TRIED stepping outside of this for specialty "performance" memory. And I've been disappointed. Compatibility problems, even when on the approved memory lists, etc.
GPU
Big fan of Display Port. My current 970 is driving 3 Display Port monitors. And, if I wanted, I could run at least two of them daisy-chained.
PSU
I agree to out-spec your PSU a bit. Blowing a PSU can destroy other components. So not getting "just enough" ensures you have some headroom.
Case
I agree about filters. Dusting cases SUCKS. Even ones with good accessibility.
I prefer roomier cases. "Quiet" cases tend to either be really cramped, or have poor general cooling.
I've grown to hate cramped cases. Too much bloodshed.
UPS: I'm running a Back-UPS Pro 1500S.
The house I bought still has the orignal 1974 wiring, plus a bunch of half-assery the previous owner tied in... So power delivery can be a bit wonky at times. Not TERRIBLY unstable. But every now and again, *CLICK*