Earth Two in the New 52. It seems like a crazy idea. The New 52 was partially meant to make the DC stories and characters accessible to new readers. Now that they're starting to become familiar with them, a completely new "universe" is being thrusted upon them. But because James Robinson is involved we know we're in good hands.
To make things even better, DC has revealed the variant cover to the first issue by Ivan Reis and Joe Prado.
If you weren't convinced about the potential of this book before, you should be now.