Writers Who Will Stand the Test of Time?

Embedded Geek asks: "Every year, the online version of Locus (a trade magazine of Science Fiction & Fantasy) asks the question: "Name the 5 deceased 20th century SF & fantasy writers you think will still be read 50 years from now." The results favored some of the bigger names (Heinlein, Asimov, Tolkein) as well as a few lesser known figures (Simak, Bester). I would like to ask a broader question: What authors (in any genre, fiction or nonfiction) alive today will still be read (hard copy or online) in 2051?" If I had to answer off of the top of my head, I know William Gibson, Charles Sheffield, and Orson Scott Card would be in my list, but that's not all of them. A few authors who I thought would be classics have since vanished (whatever did happen to Daniel Keys Moran, anyways?) aand of course there are a few iffy ones which I could be convinced on (C.J. Cherryh, anyone). What authors do you feel will stand the test of time? Yeah, these are sci-fi authors, but that's about what I read these days.