We've collected Ning Networks that have inspiring design here in the past. Here's a post on Socialbrite, where LauraO shares some of her favorites. The collection includes Ning Networks focused on commercial efforts, those that are non-profit based, as well as a couple making best use of the Groups feature.
Some will be familiar, but there are definitely a few Ning Networks new to me!
What do you think of those mentioned? Which do you think should be joining as a best-designed Ning Network?