Seveneves

Loved it! Takes you through the entire apocalypse; impending doom to apocalypse to surviving to rebuilding. It felt a little like two books in one to me.
The first 3/4 of the book are very hard sci-fi. Lots of technical jargon and descriptions for astronomy and spaceflight theory that will leave a lot of people turned off. Personally I loved it, I can say that I learned a lot of interesting things reading this book that I never knew the first thing about.
The last 1/4 of the book falls more in line with your traditional sci-fi. It's been 5000 years since the apocalypse and a lot has changed. I thought it was a great ending for the book and really can't imagine it having ended any other way.
Stephenson has said in interviews that a sequel could be forthcoming and I really hope it is. There is so much more that can be done in this story. Just one off the top of my head is the Mars diaspora. Their expedition is never mentioned again afterwards. So, that would be a great place to take it.

TL;DR Excellent book that covers the entire spectrum of an apocalypse. Stephenson is the absolute man!!