My favourite contemporary French author is Bernard Werber. I think I've mentioned him before. My favourite books by him, The Thanatonauts (Les Thanatonautes), isn't available in English, but his first books, Empire of the Ants (Les Fourmis) is.
As far as classics go, I love Les Misérables. It's full of ridiculous coincidences, of completely off-topic rants and of un-needed descriptions, but I love it the way it is. I re-read it recently, and I was shocked to realise I remembered some parts word for word. (I had only read it once before, actually).
I also really like The Little Prince, By St-Ex (Antoine de Saint-Exupéry). We actually translated it into English in university, it was pretty neat (that wasn't published or anything, mind you, it was just an assignment). This one I've read countless times, I seem to find new things about it every time even though it's so short.
I guess that's my contribution for today. A fair amount of books that were originally written in English I've read in French as a kid, so I'm working my way up reading them in English now.