I would like to see a latency map, showing the lowest latencies achieved between various destinations around the world. What is for example the lowest latencies achieved between Denmark and India. This could for example be used for planning of where to place a server farm for online games.
for a starting point.
Though I confess that I don't entirely understand your question. Surely you need to first understand where your customers are. For example, if your game becomes popular in Brazil (fifth most populous country in the world), you're really going to want to put a server closer to Brazil, regardless of whether you have a co-lo with good latency characteristics between Denmark and India :)
This site seams to give pretty good info about the whole internet.