i like Thakadu's News Map, featured on White African a few days ago. Basically, it is a Google Maps and Yahoo News mashup that captures current news stories by country in terms of "the easiest common denominator - geography" to use Erik's neat characterization. Here is a screen shot:
It's easy to visualize other useful mash-ups making use of similar mapping tools and layout. For example, one could easily replace the list of news items shown above by a list of development projects to get a new mash-up that allows a user to view projects per country or region within a country. Donors, governments, NGOs and researchers could use such a resource. Thanks for planting the thought, Thakadu!