The first DC crossover for The New 52 has been announced and it's taking place in the Batman books, under the auspices of Scott Snyder, who's writing Batman, currently in the midst of a great "Court of Owls" storyline.
The good news is "Night of Owls" is not a traditional crossover. You don't need to buy every Bat-book to understand the whole story. But the Court of Owls' attack on Gotham City, which takes place in one night, affects the entire Bat-family in their own ways, in their own stories.
I loved Snyder's Batman: The Black Mirror and Gates of Gotham. Plus his Batman is far and away the best New 52 book. I don't remember the last time I've been this excited about Batman comics. Not since I first read Frank Miller and Alan Moore's seminal Batman books in the 1980s.
Being a DC guy, I was drawn to Dissassembled and liked it a lot. So I've been led into New Avengers, and so far it's ok. The best part is definitely the art, as I just can't seem to like Bendis' writing.