Dick Meyer is National Public Radio's (NPR's) editorial director for digital media and he has a list of the top 100 20th-century novels in the English language. It's his list and he's not apologizing for it, either:

I am not a learned or prolific reader of novels. My taste is probably medium-brow, male and parochial in many ways. Tough. It's my list. I included two books that probably aren't novels: Zen and the Art of Motorcycle Maintenance and Fabulous Small Jews. Lots of innovative, modern stuff didn't make it because I am not good at reading it.

The top 10 in his list are:

1. A Portrait of the Artist as a Young Man, James Joyce
2. The Great Gatsby, F. Scott Fitzgerald
3. The Catcher in the Rye, J.D. Salinger
4. Heart of Darkness, Joseph Conrad
5. Brave New World, Aldous Huxley
6. The Grapes of Wrath, John Steinbeck
7. Angle of Repose, Wallace Stegner
8. Lolita, Vladimir Nabokov
9. Humboldt's Gift, Saul Bellow
10. A Passage to India, E.M. Forster

He links to Modern Library's list, which includes their board's list and a readers' list which, not-surprisingly, differ. The latter seems to have a few more genre works in it.

I was going to compile a list of lists of top 100 novels, but found this convenient blog post, and surprisingly, all the links worked at the time of posting. The blog is "Guldasta."