Fiction: Tolkien's trilogy
Non-fiction: Emerson's essays, first and second series
and
The Theory of Poker (yep, I'm a dork)

Arguments anyone? Anyone at all? <small>anyone????</small>

Hey, I moderate this forum now, so watch out.

Also Pet Cemetary was a multiple read for me.

Actually, "dipdork" comes to mind...

I'd agree with others that mentioned Ender's Game and Tolkien's books.

I'm not sure if I'd really include it because it's fairly recent, but George R. R. Martin's A Song of Ice and Fire series blew me away, and seems to reveal new things (symbolism, foreshadowing, etc.) on repeated readings.

I read Stephen King's IT like twenty-five times throughout my year in the fifth grade...which might explain why I am the way that I am...

other books that I have read to shreds:

Every damn book by Stephen King
The Ultimate Hitchhiker's Guide - Douglas Addams
Good Omens - Neil Gaiman & Terry Pratchett
Chronicles Of Majipoor (The Lord Valentine Trilogy) - Robert Silverberg
The Accidental Tourist - Anne Tyler

-Any book worth reading is worth re-reading - do you really think you got it all the first time?-

For me:

Small Gods (By Terry Pratchett, part of the Discworld series)
The Stand (Stephen King)
The Princess Bride (William Goldman)

i 2nd that

Harry Potter- it makes me feel like a kid again
Also Catherine Coultier- the Bride trilogy, the Legacy trilogy, and one of my favorites- Nora Roberts' Homeport.

I am just reading this for the first time as we speak. I am only 40 pages in and can already tell that it will occupy a spot in my "Top Ten Funniest Damn Things I Have Ever Read" list.

Re: the original question:

Catch-22
Watership Down
The Cyberiad (Lem)
Battle Cry of Freedom (James McPherson, the best single-volume treatment of the Civil War out there, IMHO).
Salem's Lot (King)
Lucifer's Hammer (Niven and Pournelle)
Dune
The English Patient (Ondaatje)
The Glitter Dome (Joe Wambaugh)