I'm going to narrow down my answers a bit, partly because I, too, want to go to Italy, but it's actually a case of going back to Italy to hit some places I didn't get to go when I was there.
Italy: I want to go to Pompeii/Herculaneum and the isle of Capri. (There are a handful of places I'd like to go back to, too, like Orvieto, but I'll leave those off for now.)
Iceland: I wanna see volcanos and northern lights!
Madagascar: Weird trees and plants, weird animals, and while I'm scared to death of it, Tsingy de Bemaraha could be really cool to see.