I've been fine with 32GB phones since the Nexus 6 up till my current Pixel XL - though I've been slowly creeping up on the point where if this year's options had been 32GB or 128GB, I'd have probably stepped up. With the baseline at 64GB, that's an easy choice for me.
Even more so when I figure I'll probably trade up again next year - and if the trade-in program is still a good value like it is currently, I anticipate the difference in buyback between the 64GB and 128GB will likely still be around the same $10 return on the $100 difference...