Pride and Prejudice. Not my kind of thing usually, and I'd always fought shy of it, thinking ugh, ghastly old fashioned stuff. Then, egged on by Colin Firth (not literally, more's the pity) I actually read it. And was on the edge of my seat - it is just so well written. Having said all that, my second favourite is "Reaper Man," Terry Pratchett and after that anything by Isaac Asimov. (Read TKAM at school, along with other worthy contenders such as Catcher in the Rye, Cider with Rosie and Lord of the Flies, and to be honest don't really want to read any of them again.) School also put me off Tess, that and the fact that it was written as a serial so every chapter ends with a cliffhanger, which got me down after a while.