Google Maps (EuroTrip map)
I didn't realize until recently the power that Google Maps wields. It lets you add POI's to give you a feel of how the
places you are visiting are laid out. Not only that you can approximately draw a line from these points giving a rough
reference of how far these distances are on the
map.
One thing I would like to see them incorporate is some kind of a Trip Planner like TripIt. Only downside to that is the user would have to let Google access their trip data which i suppose many people don't mind since TripIt uses the same technique. Keeping in mind the powerful ADsense Google has, suggestions about these places on one's 'Trip' could be shown making it a very powerful user-oriented Web 2.0 app.
Hopefully someone in the mysterious googleplex has the same idea on their minds.