[gradys]

Permutation City by Greg Egan - Hard sci-fi about what might happen if we could scan human minds in sufficient detail to simulate them in computers. Best treatment of this topic I've ever seen.

Diaspora by Greg Egan - Takes the idea much, much further. What might happen to humanity if virtualized "human" minds embodied in robots or not embodied at all became the two most common ways for people to be. Also, fascinating and surprisingly rigorous diversions into math and physics.

[danbmil99]

Greg Egan is a true treasure. I would love to know more about why he seems to have pulled out of traditional publishing.

[AlexCoventry]

It's from a couple of years ago, but his Clockwork Rocket series is incredible. It's about a universe in which the spacetime metric is Riemannian instead of Einsteinian.