I personally love large, diverse, multi-biome/terrain maps. I love exploring and if I'm roleplaying, claim my den. :3
Public maps, I like Flourite Plains because it's huge, and has a lot of caves and rocks and such.
I also LOVE creepy maps. I'm the kind of roleplayer that makes that one creepy (but still fun and kind) character that makes their den in the giant skeleton/bone heap.