SanDisk 64GB Mobile Ultra MicroSDXC Class 10 UHS-1 30MB/s Memory Card with SD Adapter (NEW VERSION) - Retail Packaging with Komputerbay SDXC USB Reader
It came formatted with exFAT. I plugged it in with the USB adapter into my Windows 7 PC and copied a 1.6GB movie to it. I plugged it into the docking station slot, recognized it and played the movie with no problem. I plugged it into the tablet microSD slot and again played the movie with no problem.
I have had my tablet for about a month and loving it.
ASUS Transformer Pad TF700T
WiFi version w/ 32GB + External Sandisk 64GB microSD
Docking Station TF201
Also, rebooted several times with card in tablet.
All these card and formatting issues really suck! You would think they would have all been resolved by now....and not just with tablets.