Ooh, what a wonderful thread! I have so many books that I love to read over and over that I don't know how I could possibly list them all... but I'll try.

Several other people said ones I love, but I'll still mention them.
Anne of Green Gables, by L.M. Montgomery, (and the other Anne books, but especially that one)
Emily of New Moon, by L.M. Montgomery, and all the other Emily books
Pride and Prejudice, by Jane Austen (also, to a lesser degree, Emma, Mansfield Park, and Northanger Abbey.
The Physician, by Noah Gordon.
Clan of the Cave Bear, by Jean M. Auel, as well as the others in the series.
Crooked House, by Agatha Christie.
Isle of View, by Piers Anthony, and the other Xanth books.
A Little Princess, by Frances Hodgson Burnett (did I get that name right?). Never really liked A Secret Garden, though. And never read it in French. smile
Arrows of the Queen, by Mercedes Lackey, and the other Valdemar books (but especially Talia's).
Fiddler Fair, by Mercedes Lackey.
Those are probably my biggest "comfort" books, books I reread and reread when I want the comfort of an old, familiar friend near me. The L.M. Montgomery, Jane Austen, Jean M. Auel books, as well as A Little Princess, are probably the biggest comfort books when I'm feeling down. Some of them also have movies, which, coincidentally, are some of my comfort movies as well (except for the Clan of the Cave Bear movie, which stunk).