The Long Dark Tea-Time of the Soul by Douglas Adams [re-read]
Foundation by Isaac Asimov
Foundation and Empire by Isaac Asimov
Second Foundation by Isaac Asimov
Dragon's Egg by Robert L. Forward [re-read]
Starquake by Robert L. Forward
Welcome to the Monkey House by Kurt Vonnegut, Jr.
Dark Water's Embrace by Stephen Leigh [re-read]
The back of Dark Water's Embrace compared it to The Left Hand of Darkness, so I figure I'll re-read that next as a segue into the Earthsea trilogy (which I have not yet read).
When you're in trouble, you can call
DW.