I don't think Shane is going to be killed off anytime soon. His character is the cause of too much tension in the plot--which one could argue could drive the plot to a conflict resulting in his death, but at the same time him simply being alive is a conflict in and of itself.
I think it's going to be either Lori or Andrea.
My reasoning?
Errrr...they're both dumb bitches? lol
The Black Guy, Hershel's daughters, and some of the other minor characters. Basically, it's everyone besides Glenn, Daryl, Dale, Hershel, Andrea, Carol, Rick, Shane, Laurie, and Carl.