I really appreciate, in no particular order:

• Seveneves, Neal Stephenson
• Xenocide, Orson Scott Card (third book of Ender's Game, though I may confuse w/ second)
• Ringworld, Larry Niven
• Consider Phlebas, Iain M Banks (Surface Detail from that series is fantastic too)

_{Am currently re-reading Red/Blue/Green Mars, Kim Stanley Robinson. Actually enjoying it more this time than the last.}