I've got two servers running on wargeeks.org. A "vanilla" with monsters (basic plugins for warps and homes), and a "mod" server that has bells and whistles, and no beasties at all. Mainly for building. These servers are only really used by 3-4 people at most. One of our players has built some pretty awesome things.

If you're interested, you can look at the maps: http://minecraft.wargeeks.org

The gmap folders has the google maps type interface, and the mcmap folders have the static images.