MapQuest was THE first and only web routing service I relied on. But once up on a time, I almost forgot its existence because of Google Maps, Yahoo, and even others. Recently MapQuest seems to be coming back really strong especially with its Open Initiative and integration with OpenStreetMap data. One of the most amazing things I have seen is this Dublin-to-Shanghai world-wide routing:
Although I don’t think it has much practical use to most people except for professional backpacker traveler, it is still amazing and seriously no one else can do it.