There are so many!!! Really, a book isn't any fun without a hero that isn't in a dangerous world, about to be killed around every corner!
Wow. Frankly, it's depressing how many books have setting that I would never, everevereverever want to live in... probably because I would be dead as a doornail in a second.
All these settings are supposedly Earth in the future. Yikes. Apparently, authors are all plotting to destroy our world's society in the future. (Will it be aliens, war, zombies, or a shortage of water?)
And I still LOVE almost all of these books :D So, go read them!
What are your top ten worlds?