Google Earth is great, but I notice a few limitations - in particular, the overlay of borders doesn't always exactly match the reality on the ground. Here, for instance, is a screenshot of the Albanian/Macedonian border on the south-eastern shore of Lake Ohrid (40°54'41" N, 20°44'27"E):
I know this area quite well, and in fact the large pool of water in the middle of the picture (the source of the Black Drim river) and the monastery complex to the west (left) of it are firmly in Macedonia, having apparently been given to the King of Yugoslavia by King Zog of Albania some time in the 1920s. So the yellow line is off by about 700 metres, I think.
So the lesson is, don't plan delicate details of international diplomacy with Google Maps. But do use it and say, Wow!
Especially since you can generate pictures like this:
This is one of my favourite places - the former palace of the Emperor Diocletian in Split (in Croatia, here looking roughly south). The octagonal building in the middle was built as Diocletian's tomb at the end of the 3rd century AD. It's now the city's cathedral (note large bell-tower attached to the octagon, built almost a thousand years later). Given the Emperor's record of persecuting Christians, he'd be turning in his grave (if it weren't for the fact that they threw him out of it some time ago).
And this, the work of nature rather than of humanity:
There is nothing quite like Mount Everest, is there?