What's your favorite e-classic?

What's your favorite e-classic? That is, a literary classic you've read on your e-reader? So far, mine is Heart of Darkness by Joseph Conrad. I read it on my iPhone only while pedaling a stationary bicycle at the gym, and my cardio chores went by quickly that way. Decades ago I'd read it in paperback, and the author's racist observations had been largely lost on me at the time. The writing quality is splendid, but the attitude toward Africans doesn't come close to modern standards. But it accurately reflects the times--late 19th and early 20th century, when Europeans felt that Africa was a land God gave them to despoil. But it's a compelling story with writing that's all the more impressive given that Conrad learned English as an adult.

If you're like me, you have a long list of oldies plucked off, say, Gutenberg, maybe more than you'll ever read. So if you could read only one classic, what would it be?