This thread has been resurrected twice before, let's go for three!
Contrary to many of the opinions people have given in this thread, I'll say that the book's true beauty can only be seen in its original French. A French version can be found online here:
http://www.hightech-planet.com/pdf/camus_l_etranger.pdf (the book's copyright has expired in Canada, thus it is online).
Many English translations capture Camus' writing very well, but not as well as the French version. The grammar in the book may be its most fascinating quality. Since the story is told in the first person, the grammar changes to reflect Mersault's character development. In the beginning sentences are very simple (ex. "J'ai bu.", "I drank.") and even someone beginning to learn French could understand some of it. But by the end, Camus is using very sophisticated, complex grammar.
I would recommend that everyone read the book (hell, even the half-literate George W. Bush read it during his presidency) if only for the ending few paragraphs, which are some of the most beautiful passages in all French literature (again, they're especially beautiful in the original French).
If you like Camus, I would recommend some of the writings from his early life. Camus himself, after he had become famous, did not like his early writing as it is not focused on promoting an idea or philosophical message. The beauty of the writing lies in the passion; Camus' early lyrical essays may be the most passionate, beautiful works I have ever read. They can be found in English in the collection "Lyrical and Critical Essays". I particularly adore the sub-collection entitled "L'envers et L'endroit".
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TLDR Version: Learn French. Read Camus. ????. Profit!