John's Blackest Night and the Legion of 3 worlds should be up there...well I'm excited for them. More so than the Brainiac thing.
Also secret Invasion, but I haven't read new avengers in so long, I feel I should probably catch up on that first. And I've got so much green lantern stuff to read too, to get excited about blackest night and final crisis.
I think the first issue of final crisis has got GL on the front and has stated that it was morrison who asked johns to do the alpha lanterns in the GL book.
Also fell I should catch up on Cap A, to really get into Avengers/Invaders.
Either way I think I've got some catching up to do to be able to be really excited about these corssovers. But there seems like a lot of good stuff coming out now,.