SFF - anything by Lois McMaster Bujold - I'm surprised no one has mentioned her yet.
Larry Niven, Jerry Pournelle, Andre Norton, and RAH, over the years
Children's books I read as a child, and then read to my DD - The Lion, the witch and the wardrobe, Swallows and Amazons
For cynicism - The Screwtape Letters
Nonfiction - I read a lot, so these are recent and influential: Carol Deppe, Peter D. Ward's newest books (very depressing and scary, but must reads, paleontologists take the long view)