Michael, I went through a long phase of absolutely adoring all Thomas Hardy's books, but curiously I suddenly found them infinitely depressing and fatalistic, although naturally his descriptions of rural life still delight me (especially in The Woodlanders). Jude The Obscure and Tess are enough to make one lose the will to live! But a great author nonetheless. (Studied him at Uni)
I read Jane Austin over and over again, why do we do that? I'm almost word perfect with Mansfield Park yet I go on and on reading it. The book is falling to pieces!
I have to add that many of Agatha Christie's whodunnits are very re-readable, but I suspect it's because they project one into a past age of 20th Century Britain. I have whole shelves of her, and do get stuck in frequently. I don't know what I should do without books, they're the love of my life!