Existing SD electronics can't read the SD XC format. Built-in obsolescence for those who want/need 64 gigs to store stuff.

At the local Fry's market, the clearance counter has been selling 2 gig SD cards for about 8 bucks. I picked up 2 for my EasyShare Z8612 Kodak (the big German lens is the secret to good quality photos and NOT megapixels alone! Light waves need to reach the sensor) I learned this the hard way after buying a pocket sized Fuji Finepix 9 megapixel camera whose image quality was not good even though the camera itself was very well built. Considering the miniscule amount of space it takes to hold several 2GB or 4gb cards in a camera pouch, for trips or photoshoots, the 64 XC better be priced pretty good to make it a worthwhile investment in new equipment.

I expect professional photographers and those who want more memory for movie making will appreciate the technology first.