What is the best way to move lots of photos between two iPads?
I'm a fan of PhotoSync for this. $1.99 (on the US/Canada App Stores), and can transfer between any number of devices. From their site:


  Direct transfer of photos &amp; videos between your iOS devices (iPhone,
  iPad, iPod Touch) over Wi-Fi and Bluetooth - no computer needed! Read more.


Alternatively, DropBox or even the built-in Photo Stream may help, but the latter doesn't give you much control and you're syncing photos through the Internet  in either case: PhotoSync transfers directly over Wi-fi.