In terms of the stuff I've liked:
Hobb's Assassin trilogy -- fighting, stealth, magic, politics, teen angst. This is the classic young hero angst story.
The Belgariad -- like other people said, too likeable not to like. This is the classic retro-Arthurian story.
Song of Ice and Fire -- yep. Even if incomplete, it's breaking some rules and raising the bar. This is the classic modern-gritty epic fantasy.
Pratchett's Discworld -- yep. This is the classic comedy fantasy.
Harry Potter -- yep. This is the classic young adult fantasy.
Stuff that doesn't do it for me, but should be on the list anyway:
Wheel of Time -- I stopped reading awhile ago, but it's enough of a literary presence that it really should be on the list
Mieville's Perdido Street Station -- it's vertiginously overwritten and filled with enough deliberately disgusting attempts to shock the reader with its transgression of intransgressible paradigms, or something really transgressive like that, that it left me with a bad taste in my mouth and no sympathetic character or classic plot to hold onto. That said, it's changing the genre, and I respect that.
The Runelords -- this one's borderline for me. I flipped through it but didn't like it, so I've never read it and don't intend to. That said, I've heard enough people talking about the magic system, and how it's different and interesting and actually follows some rules and such, that it seems to be kind of new and different, and I think it probably belongs on the list.
Sara Douglass -- This woman writes beautiful evocative prose. She's got some truly wonderous, tearjerking scenes in her fiction. If she could come up with anything remotely resembling a plot, she'd be a runaway success. As it is, I think her stuff has been successful enough, and spawned enough imitations, to be considered a classic.
Stuff that shouldn't be on the list, in my opinion
Feist's Riftwar Saga -- I'll suffer the flames, but while I liked it as a kid, it hasn't really stood the test of time, and reading it now, it looks pretty blatantly D&Dish and clunky. I actually like his later stuff better -- he's matured as a writer -- but I wouldn't put it up there as a classic.
Goodkind -- No. No, no, no, no, no. I don't care how popular it is, no.
Drake's "Lord of the Isles" and sequels -- this one just hasn't made as much of an impression. If I'd loved it, I might try to sneak it up there, but while the first book was decent, it didn't seem to go anywhere in the sequels, and it struck me a lot like my flip-through of the Runelords. "Wow, this guy is... pretty much... doing... normal fantasy. He's changed enough stuff to make it a bit different, but... eh." Those fantasies only work for me if they're really well written, and while the Runelords had the new magic system, Drake's stuff didn't have any special draw that made it different for me.
Modessit's Recluse Series -- I really like this series, as well as some of Modessit's other series, but I just don't think it's changed the market enough to be considered a classic.
Elizabeth Hayden -- Much like Modessit, except that I didn't like her. It's sold respectably well and built up a world, but it hasn't changed the face of the market. It's not enough of a sales powerhouse (like Wheel of Time), geek powerhouse (like Martin), or literary powerhouse (like Mieville) to qualify.
The Myth Series -- I liked it, and if Aspirin hadn't had his several-year depressive episode or drug spiral or whatever it was that knocked him out of the field for so long, I'd say that it should be a classic. But while he was gone, the field moved on without him, and I think that, while he was one of the iconic first popular comic fantasy people, he's been surpassed by enough folks now to not be on the list.
