At the top of her list:
Daniel Deronda by George Eliot -- I read this in the same 19th Century literature class. It deals with ethnicity, with Jewishness, in a way that was highly unusual and risky for a female, English writer.Read the entire list.
Mrs. Dalloway by Virginia Woolf -- I could really list any novel by Woolf. Reading her prose is like looking through calm, clear water. The language is so perfect. It does what great writing should: it illuminates, but it never gets in the way.
Lolita by Vladimir Nabokov -- Gorgeous, poetic, verging-on-mad prose. An orgy of prose, really. I read it for the first time at an artist's colony where I was visiting while writing my first novel, and I remember feeling sad, almost nostalgic while reading it because I'd never be able to read it for the first time ever again.