The 5 most impressive and/or usefull Google Maps mashups I've ever seen ... until now

Last update: 19 Oct. 08

airtraffic screenshot Air Traffic: real-time location of airplanes in Zürick (CH) air space. I'm very found of this kind of mashups. I expect a radio stream soon :)
hklkartta screenshot Helsinki public Transport Map: real-time location of buses in the city streets. Everything is there: routes, stops, locations. it's probably the most complete trafic supervision tool available to public. Amazing!
maplib screenshot MapLib: turns any pictures into zoomable and panable views. A fresh idea of what can be done by slightly diverting Google Maps of its original purpose. Quite fun to see!
shaded-relief screenshot Shaded Relief: A very beautiful demonstration of custom map types. A toolbox (coordinates, altitude, distance, area) is also available. I like it!
wikimapia screenshot Wikimapia: when maps meet wikis. A collaborative tool to add geolocated information concerning any location on earth. Very well done and absolutely usefull! A single bad point: articles are weaker than their Wikipedia counterparts.

The french mashup...

MeilleursAgents.com screenshot Meilleurs Agents: real estate price in Paris with an unprecedented detail level. I do not know about price accuracy but from both ergonomy and graphics points of view, it is a very nice work.