I'm 25, and I voted for Tolkien, Jordan (only read the first three books before I lost all interest in the Wheel of Time, though), and Brooks (my brother read more of his stuff than me).
The lack of Margaret Weis, Tracy Hickman, Mercedes Lackey, Lloyd Alexander, and especially C. S. Lewis means that many of the authors I spent a lot of my youth reading are not on this list. Even Piers Anthony was more significant to my exposure to fantasy than anyone on that list short of Tolkien. In fact, these days Shakespeare might be a more important influence on my view of fantasy than anything on that list short of Tolkien (Prospero is pretty much the definition of the classic fantasy wizard, after all). If we are moving past fantasy (which seems reasonable considering that the Discworld guy gets mentioned), then mentioning Isaac Asimov is simply a necessity.
Of course, my fondness for myth and folktales predates my interest in fantasy literature, and my interest in fantasy has been fueled just as much by videogames and anime as books. I never understood why the "fantasy canon" in these threads is always limited to just books...