The best that I can tell, the new 52 time-line goes something like...: 
 
 
<5 Years ago
 
Demon Knights 
All-Star Western
Action Comics 
DC Comics Presents: Deadman 
Aquaman
Green Arrow
The Savage Hawkman 
The Fury of Firestorm
 
 
5 Years Ago 

Justice League   
  
Between 5 Years Ago and Now 
 
Green Lantern: The New Guardians  
Superboy 
Supergirl 
Catwoman 
 
 
Now
 
Batgirl
Nightwing 
Birds of Prey  
Batman & Robin
Batwing 
Teen Titans 
Red Hood & The Outlaws 
Batwoman 
Superman 
Stormwatch 
Men of War 
Justice League International 
Justice League Dark 
Animal Man 
Swamp Thing 
Resurrection Man 
Voodoo 
I, Vampire 
Deathstroke 
Frankenstein, Agent of S.H.A.D.E. 
Blackhawks  
Suicide Squad 
Hawk and Dove 
Static Shock 
Mr. Terrific 
Captain Atom 
OMAC
Green Lantern 
Red Lanterns 
Green Lantern Corp 
 
In the Future/Across Time 
 
Legion Lost 
Legion of Super-Heroes
 
Don't Know/No established date
  
Batman: The Dark Knight 
Detective Comics
Wonder Woman

The Flash 
Grifter 
Blue Beetle 
 
 
What do you guys think? Anything you might want to correct/dispute/etcetera?

@cosmo111687: cool! Its nice to see a visual like this to understand when things are... thanks!

I would add a 100s of Years ago category and place Demon Knights and All-Star Western there.

As for Aquaman and Green Arrow there is no indication that those take place in the past (to my knowledge).

The Savage Hawkman takes place now because he's clearly been Hawkman before.

Fury of Firestorm I'd put between 5 years ago and now.

Why doesn't Catwoman take place now?

Teen Titans and Superboy definitely both take place now.

Batman: The Dark Knight, Wonder Woman, The Flash, Grifter, and Blue Beetle should all take place right now. In TDK, his villains already know him. As for the rest, DC said everything should be taking place at the same time.

Detective Comics seems to be in between 5 years and now because Joker seems pretty new.

BUT it's totally awesome you initiated this. :)

Demon Knights takes place in the dark ages. so that would be more like 1000'''s of years ago instead of just 5

Batgirl is of the past, isn't it? We're talking about 3 years after "the killing joke" and NOW they are in Bruce return (of course of his journey for Batman Inc.) But this post is a good idea

Am I the only person who noticed that the first category is less than 5 years ago rather than greater than?

The timeline that seems to work as far as i can tell is...

Year 0 = Batman: Year One

Year 1 = Joker's Debut

Year 2 = Superman's Debut, Green Lantern's Debut, Flash's Debut, Cyborg's Debut, Aquaman's Debut, Wonder Woman's Debut, Robin's Debut, Justice League forms, Darkseids first appearance.

Year 3 = Teen Titans likely form this year with Dick Grayson as leader.

Year 4 = Dick Grayson becomes Nightwing, Jason Todd Becomes Robin and subsequently dies, Batman:The Killing Joke occurs. Tim Drake becomes Robin. Knight Saga occurs. Death of Superman and some form of Reign of Superman occurs. Kyle Rayner becomes GL.

Year 5 = Contagion, Cataclysm, and No Man's Land occurs. Jason Todd is resurrected in the summer. GL: Rebirth occurs.

Year 6 = Sinestro Corp war, Brightest Day, Blackest Night all occur this year. Some variation of the events of Gang War and 52 occur. Renee Montoya dies.

Year 7 = Current year we're in.

It's becoming easier to say what books didn't occur than it is to say what did occur.

Grifter should come at the same time period as Voodoo in my opionion as at the end of Voodoo #3 we see the same creatures featured in Grifter.

@The Poet said:

@cosmo111687: cool! Its nice to see a visual like this to understand when things are... thanks!

exactly!

I'm pretty sure that Flash and Blue Beetle are in the current time line.