Being that I've read all of the comics, I can say this: NO CHARACTER IS SAFE where Robert Kirkman is concerned.
That being said, the show was originally quite different from the comics until the middle of the 2nd - 3rd season, where the storyline began to move
back toward that of the comic.
While there are still many differences between the two, I feel that many of the major character kills will remain due to the fact that they are used
to cause growth to other major characters.
I believe that the next major death will be Glenn, which will give birth to the new story arc, and make a true bad ass out of Maggie (who I feel has
inherited that trait through the comic versions of Maggie, and Andrea).
Beth's character still has room to grow on the audience, so I think she'll be fine for awhile (Kirkman
LOVES to kill off the characters that
are near and dear to the fans, and she isn't there yet).
Rick won't be going anywhere. There's no character strong enough to take the reins of the group just yet (don't say "Darryl can do it", he's a
follower through and through).
Abraham is too fresh to meet his end yet, and so is Tyreese, though the future doesn't look bright for either of them.
Abraham's posse is safe for the time being as well.
Bob seems to be getting the "Merle Treatment", in that he has recently been given a little love on the show, and endeared himself enough to become a
member of the body count alongside whichever major character bites it (Glenn, IMO).
Sasha may last past the finale, but not a hell of a lot further.
Anyhow, those are my feelings regarding what we will most likely see in the finale, and immediately after it (beginning of next season).
***EDIT***
Carl, Carol, and Michonne won't be among the dead either. I didn't even mention them prior to this because they are out of the question in my opinion.
Judith is only exempt due to the fact that they already "killed" her at the prison battle, and brought her back; the fan base exhaled collectively on
that one, though she really did die at that battle in the comic.
edit on 3/28/2014 by ProfessorChaos because: edit to add