This is either a horrible, horrible tragedy, or mana from heaven, depending on whether you fall on the DC or Marvel side of comics.
Personally, I read em all; Marvel, DC, Image, Boom, Top Cow...I'm willing to give anything a shot, because good comics is good comics, in my book.
Now, a lot of people will say that Bendis is an acquired taste and I will admit, his style of writing does not work for every hero. Then again, his plot-lines are usually great and often cemented in noir, which I am a huge fan of. His run on Daredevil is one of the best, in my opinion, and even though I am not a big Spider-Man fan, his run on Ultimate Spider-Man was pretty groundbreaking.
You can't go far in Marvel cannon without running into Bendis. Off the top of my head: Daredevil, Spider-Man, X-Men, Avengers, Alias, Powers, Fantastic Four, and that's just what immediately comes to mind. He is also responsible for huge, game changing plot-lines like House Of M, Secret War, Secret Invasion, and Dark Reign.
But Bendis is through with Marvel, at least for the time being. He has been such a Marvel household name for so long, it's hard to imagine him gone.
Then again, think about what Bendis could do with Green Lantern, Superman, Wonder Woman, the Justice League...I don't really see him for Batman, but then again, I got over Snyder's run (which was amazing, don't get me wrong) after about the 4th volume.
Here is the official announcement (tweet). Jump for joy, DC fans. For the Marvel kids, read it and weep.
Official Announcement From DC: