I might be needing a new case for the living room rig.  Those 1080 Ti's are a little warm, any recommendations for a good air flow case?

You could go old school and replace a side panel with an equal sized box fan blowing in over everything.  My main concern these days with putting an air based cooling system on the floor is making sure you get good vent filters that you clean REGULARLY, or else you end up choking it out. I'd recommend, if you wanted to do so, going water cooled with an external radiator you can mount anywhere you want to keep it out of the dust. 
 
However, in all seriousness, I don't have a specific case in mind, but anything with good bottom to top flow and good vent filters, as I already said.
 
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Well what I did was keep the same case, just replace the very old Thermal Take Water Cooling 2 system and put in an Noctua air cooler.  This let the hot air escape out of the top of the case better and the cards did cool down some.  This is on my old X79  3060X computer.  Some day a new case and a better spaced motherboard since it is not big enough to move the 3 slot gpus into as the age out.