[Rbneader]

Most anything by:
Andre Norton (Witch World novels, Scent of Magic, other sci-fi and fantasy)
Georgette Heyer (hilarious romances and murder mysteries)
Lloyd Alexander (thoughtful kids books and fantasy)
Joan Aiken (ditto)
Jane Austen (Romances and social commentary)
Patricia C. Wrede's Enchanted Forest Chronicles and Sorcery and Cecilia (Romances, social commentary, fantasy)
Diana Wynne Jones (Humor, great friendships, adventure and social commentary)

Deed of Paksenarrion trilogy and it's followup Paladin's Legacy by Elizabeth Moon (epic and thoughtful fantasy)
Lord of the Rings & the Hobbit
Harry Potter
Miss Marple by Agatha Christie
The War God's Own series by David Weber (standard epic fantasy done solidly, kind of a guilty pleasure)
Jurassic Park & Timeline by Michael Crichton
Wizard of Earthsea by Ursula Le Guin
Ender's Game by Orson Scott Card
Narnia by C.S Lewis
Blackcollar series, or Icarus Hunt, and the Star Wars series by Timothy Zahn (sci-fi adventures). It's hard to go wrong with Zahn, just avoid his Cobra series, the science is really laughable in them.

Comic series with exceptional writing:
Order of the Stick (epic fantasy adventure with humor, good plots and characters)
Avatar the Last Airbender (epic fantasy following a great award-winning TV show)

Also DM of the Rings(gaming and Lord of the Rings parody) and Darths & Droids(gaming and Star Wars parody), but they're not the same caliber as the others.

Note about Cassandra Claire - I read her stuff back when it was Harry Potter fanfics, before it turned out she'd plagarized a bunch of other people's work and then took everything down to go pro. I also picked up one of her books on a whim. I don't think she's a great writer, and I do think she's got terrible professional ethics (to put it mildly).