Most people have been amazed by Google Earth, the web version at http://maps.google.co.uk/ and Microsoft’s http://local.live.com/ but they all have different data sources.
I came across Flash Earth today that allows you to try different sources from the same browser window.
Have a look at the following link which is the centre of Hook. The warehouse on the left became housing about 18 months ago which you can see if you select one of the Microsoft options.
There’s also quite a few new conservatories..