Replay, by Ken Grimwood. I so love this book. It fascinates and troubles me to no end every time.
Here’s some of mine. I’m a mad reader, so this is an incomplete list…
Weaveworld by Clive Barker - I just love the concept, themes, and the characters. The villains are more interesting to me than the heroes - you get a fair amount of background on Shadwell and Immolata (sp?), for example, but Cal and Suzanna are pretty much blank slates. I love the mixture of styles, fantasy, mystery, horror, suspenseful “chase” scenes mixed with peaceful interludes (Cal’s night on Venus Mountain and the chase by the Scourge for example). If I had to pick a single favorite book, I’d probably go with this one. I have to say also that Clive’s Imajica is also getting up there with Weaveworld now that I’ve read it a few times. Awesome stuff.
Lord of the Rings trilogy by J.R.R. Tolkien - Sure, fantasy was around before this, but Tolkien’s work is responsible for probably 99% of fantasy released since. It’s just so well crafted, you can tell decades were spent creating it.
Discworld series by Terry Pratchett - Yeah they’re funny as hell, but if you dig a little they’re really stories about the human condition, written in ways you wouldn’t expect. Thief of time is a favorite, but they’re all great, and I re-read the series (yes, the WHOLE 25 or 30 book series) at least once a year. I love how there isn’t one main character, but different groups that are the focus of each book (the Witches, the Guards, the Wizards, etc), which keeps it fresh despite the sheer number of books.
Hitchhikers guide to the galaxy “trilogy” and the Dirk Gently’s Holistic Detective series by Douglas Adams - I love how there’s concepts kind of buried in the books that aren’t obvious on first read. For example, it took me a few re-reads to really figure out what was going on with the Man in the shack, then I thought it was one of the coolest concepts I’ve ever read. Strangely enough, the first time I ever read the first book I hated it, found it dull and not at all funny, and didn’t finish it. I picked it up again about 6 months later and thought it was the funniest and most brilliant things I’ve ever read - and still think that to this day. His Dirk Gently books are just as great, and so is Last Chance to see (which is about wildlife conservation, but has the same classic Douglas Adams Humor we all know and love). We lost a great, great author when Douglas died.
Fahrenheit 451 by Ray Bradbury and 1984 by George Orwell - I read both of these in grade school but didn’t fully understand the concepts until much, much later. By the time I re-read them I was already convinced our society was becoming “blandville” and it was obvious that the originality and intelligence was being sucked out of our movies and television. It was so great to see that other people had similar ideas long before me, and expressed them in ways I never could have. Also Brave New World by Aldous Huxley, White Noise by Don DeLillo offer similar concepts, and are re-read on a regular basis.
Death Gate Cycle by Margaret Weis and Tracy Hickman - They’ve cranked out Dragonlance books by the score, but this is a very original and interesting fantasy series about how the earth was “sundered” into different realms. Yeah, it’s got the classic dwarves, elves, and whatnot, but its a really standout series in an overcrowded fantasy genre where every book involves the “boy of destiny” on a journey to get the magic widget and save the world.
Darwath Trilogy by Barbara Hambly - Another fantasy series but with a very different take. Almost more of a medieval fantasy that happens to have a little bit of magic and wizardry in it. It’s got a bit of horror elements too, the series is about how humanity is threatened by strange beings only known as “the dark”. Very character driven and deeper than most fantasy books are, which is why it’s a favorite and re-read now and again. There were a few other books added to this series later, some were ok, some weren’t.
The Cyberiad by Stanislaw Lem - I love this book because it’s so wonderfully bizarre. It’s basically a series of Norse/Greek God type stories (parables?), but the two main characters are superintelligent (and somewhat arrogant) robots…
Phillip Dick Hard to pick out a single book, this guy wrote a mind boggling amount of bizarre sci-fi type books and stories, some of which have been made into movies (Blade Runner, Minority Report, Total Recall, Paycheck, etc). Short story collections are awesome, the books are a bit deeper but just as enjoyable.
Never read a book twice. ever. why? I know how it turns out.
Another vote for Sherlock Holmes . I wait a year or so between re-readings so that I forget how each story ends. I also reread Lolita a hell of a lot. But that doesn’t say anything about me at all 
Franny and Zooey,
Raise High the Roofbeam, Carpenters & Seymour, an Introduction,
Nine Stories,
The Catcher in the Rye
by J.D. Salinger… why: because every time/age I read them I take something different away from them…
Ouch. That was like an arrow through my little book-lovin’ heart. 
I don’t read book to find out how they turn out. Since I read a lot of historical fiction and love fairy tale retellings, I know how they turn out even before I read them the first time: newsflash, Anne Boleyn is dead! I read them to enjoy the experience in my head - the sights and sounds and smells and emotions I feel when I read. It’s like an inner 3D all senses included movie that’s just for me. And it’s the BEST movie ever, because my scariest thing ever is really scary, and that’s what lurking the The Dark Woods, not someone else’s idea of scary. The Handsome Prince really is breathtakingly hot, because he’s *my *personal ideal. Some books I read and I thrill to the idea of acting the part of one or more of the characters were this book a movie, and some I savor the notion of *being *one or more of the characters. And all that can be experienced the second or seventieth time I read the book just as well as, or possibly even more effectively than the first time I read it.
But yeah, IF all I read for was to know how it turns out, I don’t think I re-read anything, either.
I dislike reading books a second time no matter how much I enjoyed them the first time, because I always think of all the books I’ll never read once I die. There’s no time to waste rereading.
That said, there have been a few. I read *Fear and Loathing in Las Vegas * twice on the same trip in Europe: once in Switzerland, once in Austria. I used to read Thailand: A Short History, by David K. Wyatt, once every year or two. It was a good overview, but I stopped after a few years once I got to know Thailand and the book itself very well. (Wyatt just died a year or two ago.) The Penguin History of the World, by JM Roberts, a book that will make you feel completely stupid for all the stuff you didn’t know. And A History of South-East Asia, by DGE Hall.
One book I would love to reread is *Remembrance of Things Past * or In Search of Lost Time (depending on the title translation), by Marcel Proust. I would love to go back over it knowing what’s in store later on, but I don’t want to spend another year reading it like I did before!
Ah yes, and The Oxford Illustrated History of Medieval Europe, edited by George Holmes, a truly fascinating book. And The Story of English, by Robert McCrum, William Cran and Robert MacNeil.
Lots of science fiction fans here. Me, not so much. I have yet to find a SF that makes me sit up and want to read the rest of the books by (insert name of author here). I’ve read some good SF, but it’s not my thing.
Reading for escapism for me is Georgette Heyer, Jennifer Crusie, Mary Stewart, and tons and tons of murder mysteries: Rendell, Tey, Christie, Yorke, George (until she ruined her series), Allingham, Sayer, Marsh, Grimes (she wore on me, too). There are a few Canadian and American authors’ series that I have read and enjoyed, but I cannot recall their names at present. (Sadly, I tend to remember plot instead of title or author-not real helpful).
Fantasy books I reread include Tolkien, Juster (I like to reread Phantom Tollbooth every few years), Langley, Rowling (not so much now that the last book is over and done with), Mary Stewart’s Merlin Trilogy is superb; the Pern series that I just reread and must say I didn’t find all that riveting this time around. I’d like to find a fantasy author (or SF) that I could read all through. I have found I don’t like alternative histories as they are currently written/marketed. I prefer more suspense/supernatural/eery stuff to gore/vampires/horror. I’d rather someone had telepathy and used it in the book then be undead or whatever. Any suggestions? PM me so as to not hijack the thread.
Books that aren’t froth that I reread because I learn from them: Oliver Sacks, Annie Lamott (hate her fiction); Bryson; Raverat–a granddaughter of Darwin and her lovely book about growing up as such in Cambridge; Sedaris (ok, I don’t learn much from him!), Rouche, Gonzalez-Crussi’s classic, On Being Born; history books (although I haven’t read any in a long, long time), no idea what this genre is called but books about living/traveling in a foreign land.
I reread to revisit old friends, to work out emotional difficulties in my head–I will remember that suchandsuch character faced X challenge and read about him or her to help me with my own. I also read to just check out of the frequently painful world. If times are very painful, I find my patience for narrative is short and so turn to poetry. Sometimes I just want to get lost in the beauty of the prose. There are as many reasons to reread books as there as not, I suppose.
One thing I have achieved: I give a book about 50-70 pages. If I am not either challenged by it or enjoying it, I don’t finish it. Life is too short and there are too many good books out there. I also will not buy a book unless I know I will reread it. Books are too expensive and I have too many of them to just go out and buy.