Hugo was the greatest storyteller of all time: the tightest structures (with some exceptions), most integrated themes, most complicated yet logical plots, almost addictive tempos (leading to breathless resolutions), thoroughly fascinating scenarios...

My three favorites (in order) are: Notre Dame, The Man Who Laughs, and Toilers of the Sea. Of these three, Toilers is the one I most like to read over again. It is tighter than any other work by Hugo. It has the least complication (think Notre Dame, but with less complex characters), yet its climax/resolution displays the same brilliant fireworks of his other works.

I have not read any other translation, but I find Isabel Hapgood's to be radiantly clear and almost poetic in its style.