I would not try to read nuances into questions like "Who in Colorado gets the driest snow?" As noted in the charts at the bottom of this page water content can vary by storm within an area: http://126.96.36.199/~bestsnow/snoqlnet.htm . In the avalanche paper note that some areas have different seasons falling into different classifications.
I don't make any assumptions about expected water content other than the broad
IMHO most of the best powder skiing comes from the intermountain regions which combine high quantity with relatively low water content: the Wasatch, Tetons, Selkirks and Monashees. Japan midwinter is similar. Finding a continental climate with high enough quantity to avoid bottoming out isn't easy. Wolf Creek and Steamboat probably are the most promising, based upon both numbers and reputation as noted by posters here.