I personally like a Portuguese book called "Os Maias" ("The Maias", with an "i", its a surname), from Eça de Queiroz and also the Brazilian Machado de Assis´s "Dom Casmurro" (it´s the same in English, only that they write it "Don" and not "Dom"). I think they are the finest examples of the Brazil-Portugal literature.
I haven´t read many American books but I liked "The Great Gatsby".