Ha. I didn't think anyone in here are avid sci-fi book worms.
I got quite a few to recommend if you guys are into this stuff:
1. One of my favourites:

2. The foundation series is awesome

2.1 Prelude to Foundation
2.2 Forward the Foundation
2.3 Foundation
2.4 Foundation and Empire
2.5 Second Foundation
2.6 Foundation's Edge
2.7 Foundation and Earth
3. You're not a true sci-fi fan without reading DUNE (at least the Frank Herbert books)

3.1 Dune (1965)
3.2 Dune Messiah (1969)
3.3 Children of Dune (1976)
3.4 God Emperor of Dune (1981)
3.5 Heretics of Dune (1984)
3.6 Chapterhouse: Dune (1985)
4. In the last couple of weeks I've been reading the OLD MAN's WAR series from John Scalzi - quite an unique universe

You'll find all the books of the series here:
https://www.goodreads.com/series/40789-old-man-s-war