Well, I can help you with DC comics but not Marvel as I am a an active reader of them.
Anywho.. in a nutshell.. lets do this. (all stuff is from a month ago, havent gotten my comics this week)
As for Superman dying.. that was so many years ago it dosent really matter anymore, except they are having some sort of special thing coming out about what the characters thought of that day. Doomsday (the thing that kicked his butt) was supposedely thrown to the edge of the universe but then came back and the government put him in holding.. or something like that. Superman also was changed a few years back to a blue energy superman to try to get more interest in him, but that flopped and he is back as being plain old Superman again.
Lex Luthor is president of the USA after helping out Gotham when it had a huge Earthquake.
Lex Luthor knows who Superman is, as in Clark Kent. So does some dude named Manchester Black.
For the past year everyone thought Acquaman was dead after some huge universal war, but they just found him 2000 years ago in the past in old Atlantis.
Bruce Wayne went into hiding when the coppers thought we murdered Vesper Farchild but a bunch of months later (and way too many crossovers for me to bother reading) he was cleared and came back out of hiding.
Yeah.. so I gotta go to work now. Hope that helps some.