dark base 900?

@For Science! those are nice but they're $199.90 . XL R2 is currently $144.10 and the 750D is $156.99, so noticeably cheaper. Think the BQ case is worth the extra?

Will be for this:

PCPartPicker Part List: https://pcpartpicker.com/list/t2x6Nq

CPU: Intel Core i7-970 3.2 GHz 6-Core Processor  (Purchased For $16.25) 
CPU Cooler: Noctua NH-D15S 82.52 CFM CPU Cooler  (Purchased For $79.95) 
Motherboard: EVGA 170-BL-E762-A1 XL ATX LGA1366 Motherboard  (Purchased For $248.95) 
Memory: Kingston Savage 8 GB (1 x 8 GB) DDR3-1600 Memory  (Purchased For $30.00) 
Memory: Kingston Savage 8 GB (1 x 8 GB) DDR3-1600 Memory  (Purchased For $30.00) 
Memory: Kingston Savage 8 GB (1 x 8 GB) DDR3-1600 Memory  (Purchased For $64.95) 
Case: Corsair 750D ATX Full Tower Case  ($156.99 @ Newegg) 
Power Supply: EVGA SuperNOVA G3 1000 W 80+ Gold Certified Fully Modular ATX Power Supply  (Purchased For $130.00) 
Total: $757.09
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-02-17 13:05 EST-0500

Don't currently have the case ofc, and don't have a GPU/GPUs decided on yet. 

I was recently looking at XL-ATX cases (for Gigabyte TRX40 boards) and really struggled to find nice cases. In the end I think I came to the conclusion of O11-Dynamic XL, Dark Base 900, Cosmos C700M.

XL R2 is good on paper, just a bit old fashioned, but I think is okay otherwise....

What kind of look and function are you going for?

More of a look that fits the hardware I guess. I may decide to go full anti-aesthetic and run classic brown noctuas and such, not caring about matching anything. Or I may do a cleaner/more matched color scheme build, IDK. The board is red/black so really it can go with any black case without issue. It's from 2009 so it'd fit a more old fashioned style case, but again, being a clean black PCB with red accents it can fit right in a lot of modern stuff. 

All those cases look quite nice, I guess the main concern is airflow to the CPU? They all have 5.25" drive bays in the top section, but from pics it seems the DB900 does let me do the cool inverted layout thing? Depending on what GPU I decide to go with that could be cool, since it lets you see the main part of the cooler, not just a PCB/backplate. 

Oh and the DB900 does have the best WC compatibility of the bunch AFAIK, but I've been tallying up how much I have in PC components so far and uhhhhhhhh..... yeah custom loop probably not the best idea, if I were to do another one it'd be for my SR-2, but that needs even more work.

Yea I like the modularity and customization space of the DB900 a lot, not many cases let you remove the PSU shroud all together these days....My only gripe with it is that it sacrifices air flow over noise, meaning that I will probably crank up the fans, and subsequently end up with more noise....

True.... but only the 750D Airflow looks to actually have better, well, airflow. At least for the front 2 fans below the 5.25" bays. The XL R2 is a similar flat front plate with side vents design. In my experience it doesn't hurt a lot through, my Define S has no problems cooling stuff. Just sadly it can't fit any of the motherboards I wanna keep, because they're all EATX or larger  (it can fit them if I cut important parts of the case out... but then I have to cut important parts of the case out). 

Are you more concerned about airflow, noise, or future custom watercooling compatability?

@TVwazhere I'd say airflow. I'm down to slap NF-F12s to max for bench runs so I don't care about noise (and both of the rigs I'll be using full time are basically inaudible anyways), and eeeeeh for this specific rig I don't think I'd invest in watercooling, especially since the GPUs I'm using don't really have blocks available.

I'd say the 750D then. One of the last great great full towers Corsair made IMO

Got it. Barely, they had one left in stock. 

But it shall be mine Friday:

Pretty sure this: "One of the last great great full towers Corsair made IMO" coming from the LTT Case Daddy is justification enough for a near-impulse buy? 

And with prime shipping too!