First came IDENTITY CRISIS. Next comes DC COUNTDOWN. And, as stolen from www.geoffjohns.com:
1. Donna Troy died.
2. The return/arrival of: a "new" Supergirl, the original Hourman and Hal Jordan as Green Lantern.
3. A new Firestorm, "death" of Ronnie Raymond.
4. A new 7 Soldiers re-imagined by Grant Morrison.
5. War Games in the Bat books that broke up the Bat-crew and put an end finally to the "Batman is only an Urban Legend" nonsense. Batgirl and Robin in Bludhaven, Oracle and Black Canary and Huntress take to the skies, Nightwing -- Dick Grayson -- is largely MIA and Batman largely alone in Gotham with the GCPD against him.
6. Re-booted Legion of Super-Heroes.
7. Re-booted Doom Patrol with the original DPers.
8. Murder of Sue Dibney, secret about the Power Pact and the brainwashing comes out, Robin's father dies, Captain Boomerang dies and is replaced by his son, Jean Loring is a murderer, the heroes don't know who to trust.
9. Wonder Woman is blinded.
10. Many of Hawkman's arch-enemies are coming out of the woodwork.
11. Black Adam has taken over his native country of Khandaq as dictator aided by Atom Smasher, Northwind and the Feitherans.
12. Aquaman is still banished from Atlantis, half the city of San Diego falls into the sea in an incident manufactured by an unknown cabal and the surviving Sub-Diegans turned into water-breathers who die on land (except for Lorena/Aquagirl).
13. Mia becomes Speedy and is diagonosed with HIV.
14. Adam Strange "loses" his wife and all the other stuff going on his book.
15. Hawkwoman (Shayera Thal) re-appeared briefly in Hawkman but then returned to Thanganar ( in time for the Rann/Thanganar War? )
16. The CSA of Earth-2 return.
17. The mention of a Jim Corrigan in Gotham Central, and the fact that he's a crooked cop.
18. Mr. Mxyltpyx mentioning of a crisis soon.
19. In the "Titan's Tomorrow" (10 years into the future) storyline there is talk of a Crisis.