>>412489359
64gb is plenty, /especially/ if you mostly intend to use it for PCVR.
If you buy a new Quest2 now, 128gb is the lowest storage tier available; the 64gb version has been phased out, so you'll only see that if you get a used one.

There are silly large standalone games like Medal of Honor at 42gb, but the vast majority are in the 1-3gb range. Not that you are likely to ever want to play the standalone version over the PC version, except when there is no PC version available ( e.g. Resident Evil 4, size 15gb ).