Rats. I was hoping I could vote for both on this one. Oh, well.
My fantasy world would consist of all natural people co-existing peacefully with dinosaurs (think "Jurassic Park" but without the dinosaurs eating people). In this fantasy world, the weather would always be pleasant with maximum temperatures in Summer of 75°F (no higher) and minimum temperatures in Winter of -15°F (no lower). It would rain (or snow) when needed. In addition, technology would always remain in the 1970s to the 1990s with no further advancement needed.
That's the fantasy world I'd want to live in. Pity the real world doesn't work like that.