I read a lot, and nearly always new stuff, but there are a few books that I revisit every so often:[ul][li]Shroud for a Nightingale by P.D. James[/li][li]Watchers by Dean Koontz[/li][li]The Return by Joe de Mers[/li][li]Timeline by Michael Crichton[/li][li]Dibs in Search of Self by Virginia Axline[/li][li]Blue Streak: Swearing, Free Speech, and Sexual Harrassment by Richard Dooling[/li][li]Replay by Ken Grimwood[/li][li]All Creatures Great and Small by James Herriot[/li][li]Air Force One is Haunted by Robert Serling[/ul][/li]A mix of fiction and nonfiction, natural and supernatural. It’s been a long time since this list has changed…I wonder what the next book added to it will be. 
There are some books I’ve re-read pretty often.
I’ve re-read Lord of the Rings sp many times I’ve lost count. well over 20 times, though.
I’ve re-read Frederick Forsyth’s Day of the Jackal many times. I love his crisp, straightforward descriptions.
I’ve re-read many Robert Heinlein books. Again, he has an arresting style. I have three of his books unabridged on audio, and that drives the average up, but I’d already re-read two of those many times over.
Dune
Several plays. I’ve re-read Neil Simon’s plays many times over, and Shaw, and Robert Bolt and both Shaeffer brothers.
Dave Barry’s books
Back when I had more time and less money, I reread often.
Now it is rare. But I sometimes regret that I don’t visit my old friends more.
I re-read Tolkien (starting with The Hobbit, then The Lord of the Rings, then the Silmarillion) every five years or so; I’ve probably read the lot of them 6 or 7 times now.
There are a few fantasy and sci-fi series which I’ve read two or three times. Unfortunately, I’ve found that, in many cases, I don’t enjoy them as much the second time around. It’s not that I’m not surprised by the story, it’s that I start to get hung up on the author’s crutches and plot devices – such as Stephen R. Donaldson’s use of overblown, strange adjectives, or the fact that if David Eddings puts a country on a map of a fantasy world, you know that the main characters will have to visit that country at some point during the story.
I re-re-re-reread Eddings’ Eleneum and Tamuli series. I finally stopped by virtue of giving the books away in a Doper book exchange.
I later got my hands on two books in an earlier series of his, and had no compulsion to repeatedly reread it.
I am a very “Faddy” reader, so a lot of books aren’t written well enough for my personal taste.
But without a book on the go I get withdrawal symptons, so rather then read nothing at all I’ll reread some authors, like Patrick O’Brien or Pterry.
Some books I enjoy immensely when I first read them but i can’t enjoy reading them again.
I haven’t analysed it but I suspect that the more complex the content (plus of course a high standard of writing) and the more varigated the plot then the easier it is to enjoy them again.
I enjoy “Who dunnits”, usually historical ones but for obvious reasons only read them once.
I have some favorites that I re-read from time to time.
Josephine Tey’s The Daughter of Time
Sherlock Holmes stories
Ernest Hemingway’s The Sun Also Rises
Re-reading a favorite book is kind of like putting on a favorite old sweater.
I mostly re-read. It’s like having another conversation with a good friend. I want to re-read books to immerse myself in the prose, to enjoy the characters, to re-hear interesting or funny dialogue, to travel along with the author and hear their thoughts. I pick up things I hadn’t noticed the first time, I find myself connecting with different character or ideas at different times in my life.
I have a reasonable collection of books I re-read most often. Anything by Robin McKinley, Pride and Prejudice, Tolkien, C. S. Lewis, G. K. Chesterton, Terry Pratchett, Marilynne Robinson, the Anne series, Nigella Lawson, John Thorne, Tad Williams, Lynn Flewelling, Jane Eyre, Laurie Colwin.
If I like something I’ll re-read it.
As mentioned in previous threads, I am an avid re-reader. There are many books that I have read dozens of times, and I estimate that I have re-read my favorite book at least 250 times. I am also constantly reading new books. With my Kindle, I divide new books I read into two categories: will probably never re-read (sent to the archive) or will probably want to re-read (kept in a special category, which currently contains 16 books). I have also put some of my favorite books to re-read on the Kindle, so that if I feel the urge, they’re instantly available. In fact, that was one of the primary advantages of the Kindle for me. It’s magical to me that I now carry my favorite books with me at all times.
I should mention that I also own over 30 T.V. series on DVD, for the same reason – so that I can rewatch them whenever I want.
I’m not going to vote in the poll because I’m not a reader. I’ll read MAYBE one book a year. Maybe. Previously I read more but not like any “reader” would.
However, when I do read, it’s probably 75% recycled. So I don’t know if I’m a “rarely…” since I rarely read, but when I do it’s half and half recycled. Heh.
I’ve read Neal Stephenson’s Baroque Cycle twice, and that’s a lot of readin’. My favorite book, about the early days of baseball, I’ve read maybe four times.
I’m like SpolierVirgin with TV, too. In fact, I don’t really have time to read because I’m watchin’ TV.
It’s funny - I reread sparingly but do visit some favorites every now and again, but right now I’m just rereading a trilogy I read in high school (Barbara Hambly’s Darwath books) that I had to hunt down because it’s now out of print, and it’s even better than I remembered it. Why on earth is it out of print? I need to hunt down a set for my nephew (I mean, they’re like a buck a book on half.com, but it’s still a pain.)
I love to reread my favorite books and I’ll give in to the impulse quite often. In the last year, I’ve tried to limit the habit, just because I have so many new books sitting on my shelves. I’m a member of www.paperbackswap.com, so I find I rapidly accumulate new books without spending a lot of money on them.
There are some books that just have to be read again. I don’t think I could ever come to a halfway decent understanding of House of Leaves without reading it at least twice. Some would call that a waste of time, but I call it getting my money’s worth. Are there lots of other books out there? Yes. Should you try to read a lot of new stuff? Yes. Are you going to read every single book out there? No.
And sometimes there’s just something comforting about rereading a good book. It means you can enter that world again and immerse yourself once more in a good story. Sure, you already know what happens, but in a way that’s comforting, too (in that you can relive the stuff you like, and skip the stuff you don’t). And, like others have said, sometimes you miss things the first time around.
I re-read, but not often. I have to really, really, like a book before I’ll re-read it. For a book, it’s the highest honor I can pay.
And my honor roll of re-read books:
Down the Common by Ann Baer
Gone with the Wind by Margaret Mitchell
A Walk in the Woods by Bill Bryson
Dave Barry Does Japan by Dave Barry
Pride and Prejudice by Jane Austen
All the Little House books by Laura Ingalls Wilder
Candide by Voltaire
I, Claudius and Claudius the God by Robert Graves
There may be a couple of others I’ve left out.
The nice thing about being me is I often forget whodunnit anyway. Whee! It’s like new! 
I read Neil Stephenson’s Cryptonomicon about once a year - it has geeks and WW2 in a mixture that’s just right for me. It’s certainly one of my Top 3 favorites. I’m close to destroying my trade paperback of it and will have to get it on my Kindle soon. I also read a selection of Heinlein books once a year - always including The Moon is a Harsh Mistress and Starship Troopers, then rounding out with a couple-three of his “juveniles”. I’ve re-read the Dresden Files and Song of Ice and Fire series each at least two or three times.
I chose “sometimes” also, even tho the last part isn’t really accurate for me. I’m kind of like Eleanor, in that I will re-read a good book if it’s been a while since I last read it, or if for some reason it pops into my head, or if a sequel is coming out. I rarely get rid of books I buy, tho, so that I will have them on hand to re-read, unless it’s a crappy book, in which case it gets sold to the used book store or donated to the library (hey, somebody else might think it’s the best book since Sliced Bread).
I very rarely re-read, but I do have my favourites that I like to enjoy more than once, most frequently Discworld but not exclusively.
Lately I’ve found it hard to find new authors I like. I don’t have a library convenient to me, and buying $30 books and being disappointed by them has become far too common, so all I’ve been doing for the past couple of years is either not reading as often, or re-reading some I haven’t read in quite a long while.
I’ve just finished one I hadn’t read since I bought it about ten years ago, and now I remember why I hadn’t ever thought to re-read it - it was awful. But I do usually like the author so I consider that one an anomaly.
I get tired of risking my time on crappy novels. So I will reread the books that I know will satisfy me.
I read so quickly, I often find that when I reread books I pick up on stuff that I missed the first time around.
I once read Feet of Clay by Terry Pratchett five times in a row, and every time I noticed a detail that I’d missed previously. (I’d got it from the library and wanted to make the most of it.)
I have a terrible habit of reading books without realising that they’re in a series, as well, so sometimes I have to go back and reread in the light of what I’ve found out through subsequent stories.