I was inspired by the "show me your Newcrest" post, and thought it would be fun if we showed each other all our worlds and what we've done with them. All worlds in one post, however, would be way too ...
I do the same as @Stormkeep and @JAL - I have even spent weeks setting up every world so that I can keep a base save to play any new games from. And when I get a new pack with a new world I always set up that world before I will start playing it.
So, here is my Oasis Springs, I haven't yet gotten around to all the families in my rotation: https://dl.dropbox.com/s/qucibfk1n5q51ww/Oasis%20Springs.png?dl=0
The Parched Prospect area (starter homes), which currently houses my Thompson family, the Lotharios (with a child-aged Don), the Dreamers (with a child-aged Darren) and the Brokes (with a child-aged Skip):