Oooh, the books are SO good. The series is good too, of course. I would dig a prequel a la Wolf/Walking Dead by Telltale. I don't know, if they go the way of some of the other movies that have gone to video game it could go either way. I typically stay as far away from those games as possible because, well, quite often the games just suck.
If they did such an epic undertaking as Skyrim then well, yeah, it would be great. Oftentimes it seems that the developers don't put nearly enough effort into games based on shows/movies (even though this is originally a set of novels, it gained tremendous popularity when it appeared on HBO, so for sake of the thread, I'm calling it a show/movie).
I have a feeling Telltale can pull it off. I didn't think they could make a good standalone story to The Walking Dead but somehow, they did, as marthyrocks said. But we can tell if they'll base the game on the novel or show/movie IF the characters look anything like they do in the TV series. Either way, I know it's going to be good. Telltale can do it, I know they can.