Books: Le Petit Larousse Illustré
I started learning French as a freshman in high school, and I've always wanted to get more proficient at it. One of the stumbling blocks a student of any foreign language finds is that the translation-type dictionaries ("French to English/English to French") soon fail to capture the exact nuance or meaning of a word in its native form. French, for example, is not a code or a funny translation scheme for English. That is, "bonjour" does not exactly equal "hello," and not every French word has an exact English analogue.
So after you've progressed past the "Comment allez-vous?" phase, you need something that can force you to think of the meaning of French words in terms of other French words. That's where the Larousse encyclopedic dictionary comes in. Containing 1800+ pages (with most in full color) and thousands of entries for French people, places, and things, this is the kind of intermediate level reference work that will serve people slugging through Camus' "La Peste." There is no English here - all the entries and definitions are in French. The only real knocks, I think, are the lack of individual pronunciations for each word and the somewhat simplistic nature of the definitions.
If you get even better at comprehending French, I can only imagine that the best dictionary will be something French college students buy for reference.