Vanity Fair was sort of an obligation read for me (I'm a compulsive accumulator of books, but also feel obliged to read anything on my shelves, eventually), but I found it a pleasant surprise. There was something about the serialised format that kept the pages turning, Thackeray's authorial voice is just the right side of self-deprecating, and Becky is a thoroughly enjoyable anti-heroine. I'd recommend it. :-)

(I also blogged about it here:
http://evesalexandria.typepad.com/eves_alexandria/2006/09/a_viper_in_the_.html )

Oh, and ditto on having read Watership Down more times than I can count...!