Like Strider, I also read several books at once, anywhere from two to half a dozen. I guess I'm a voracious reader with a short attention span, probably instilled in me by too much television in my formative years. (Even when I read, the program has to change every half hour or so!) Or maybe it's just my instinctive way of coping with the oft-cited dillemma of "so many books, so little time."
Right now, I'm reading War and Peace in a new translation, a biography of Shakespeare by Michael Wood, Ovid's Metamorphoses, and a stack of classic Westerns by the likes of Max Brand, Will Henry and Zane Grey.
Like Isabeau, I re-read my favorites every ten years or so, some every year.
I have recently revisited The Lord of the Rings, Titus Groan/Gormenghast, The Illustrated Man, and The Moon Is a Harsh Mistress.
My favorite authors are Robertson Davies, Evelyn Waugh, Ray Bradbury, P.G. Wodehouse, Rex Stout, Mark Twain, G.K. Chesterton, John D. MacDonald, Charles Dickens, William Shakespeare, Fyodor Dostoevsky, Robert A. Heinlein, C.S. Lewis, Patrick O'Brian and George Macdonald Fraser. (I could post at length on each of these, but I'll restrain myself.)