a positive utopia
(utopia = "Non-place"). Opposite of dystopia
Generally not used in its pure form in books because of the lack of tension. For exmaple, in The Dispossessed an eutopic society encounters and attempts to change a dystopic society. (Of course, these terms are subjective: one man's eutopia is another's dystopia.)
Another term that's important in "utopiology" (I'm not sure whether or not I made that one up) is anti-utopia. As opposed to simply being the opposite of eutopia, a anti-utopia is a direct crticism of a eutopia.
And example here would be 1984 and Brave New World, 1984 is a anti-utopia of the communist eutopia and Brave New World is a full-fledged dystopia.