Ever since the time I came across a late-Victorian book review that argued that Mrs. Humphry Ward would be remembered once George Eliot was rightly forgotten, I have been rather chary about predicting the canonical afterlife of any particular author. As I've said before, after about a century or so, there's a sudden shaking-out of formerly well-regarded authors and texts (Anne Manning's Married and Maiden Life of Mary Powell, afterwards Mistress Milton, for example, described in one of its Everyman editions as a "minor classic," only to magically vanish into obscurity). However, this never stopped anyone from playing the survival game.
This Metafilter thread, though, reminded me that there's an entire subcategory of the canon that has everything to do with an exceptionally powerful idea, narrative drive, and/or character--a story so compelling, for whatever reason, that its technical and stylistic flaws, if any, sink into insignificance. So, if you like playing the game: what pop novels are going to survive--horror fiction, SF, mysteries, westerns, the works? What's going to be the next Frankenstein, or Dracula, or Strange Case of Dr. Jekyll and Mr. Hyde? Who will be the next Arthur Conan Doyle or Mary Elizabeth Braddon?
I'll start by making off with the super-ultra-obvious example. I think that over a century from now, we will still read at least some Stephen King: Carrie and the novellas comprising Different Seasons. Or, at least, two of the novellas from Different Seasons--"Rita Hayworth and the Shawshank Redemption" (filmed as The Shawshank Redemption) and "The Body" (filmed as Stand by Me, the subject of the Metafilter thread above). Carrie, for example, evokes the adolescent persecution of anyone "different" in ways that resonate well beyond the novel's immediate small-town setting; I suspect that, like Dracula, which it also resembles structurally, Carrie will stand up to considerable twisting and appropriation. More to the point, it's effective horror that makes good use of its narrative form (the "memoirs," newspaper fragments, straightforward third-person omniscient narrative, and so forth).
Your votes? Bonus points for anything that might not have a NYT bestseller list-type audience now, but you think nevertheless could have real staying power.