Lord Jim
Two Years Before the Mast
Leviathan
A Tale of Two Cities
D'artagnan Romances
The Gallic Wars
Lives of the Caesars

There's a bunch more, but these are fantastic.

Sunset Song by Lewis Grassic Gibbon, rest of his A Scots Quair trilogy but that most often
Creation, Julian, Burr and Lincoln by Gore Vidal
The Man in the High Castle by Phillip K. dike
Most anything by Kurt Vonnegut

Those are books I reread every couple of years. Must of reread Sunset Song over a dozen times now

The Zombie Survival Guide and The War Z by Max Brooks "you can skip recorded attacks"

Here are a couple.

The Book Thief- about six times
I am the messenger- four
Lotr trilogy- twice
The hobbit- twice
First four of the hitchhikers guide to the galaxy (couldnt find the other ones)- three times
Jurrassic park- twice
Prey-twice

And others I can't think of now.

LOTR is one of the most (homo)erotic novels ever.

The books that I've read and re-read the most are:
The Handmaid's Tale
Brave New World
Clockwork Orange
1984
1985
Mixed in with lots of Foucault like The Birth of the Clinic and The History of sixuality VI&II, as I did my dissertation on methods of control in dystopian literature.

As for non fiction (and non Foucault) books, I always like going back to read
The Buried Soul: How Humans Invented Death
Word Freak
Anything by Nancy Friday