File Island, Digimon World
I know this place better than my neighborhood. And it's always been in my head of what the Digital World would be.

Hydaelyn, FFXIV
What BoB said. Such a pretty world.

Gamindustri, Neptunia
It's video game world.

Asuka and Amaterasu Servers, Digimon World 3
They were fun places to explore and had a lot of neat stuff. I kept getting lost in the tunnels though.

NIER's world
It's so pretty and the music is outstanding.