I love reading about the coding adventures and the how-tos that people are posting on blogs about hacking Google Maps. Everyone seems to really be having a great time learning about how Google works and combining this with their own knowledge of customizing it to something that they want. This link is no exception:
David has created a combination of Google Maps and TerraServer map interface of a point near the White House in Washington DC, USA. On the map you have the option of viewing a Topographic, Black & White Overhead, Urban (All TerraServer views) and Street Map and Satellite view (which are all the Google Maps views). It uses the same zoom tool that Google Maps does. I'm amazed with the detail in the "urban" view and it even looks a bit better than the Google Maps satellite view. This is really an awesome marriage of two different mapping tools. I just hope David makes more!