Today, Google Maps launched the new Street View feature, and I’m very impressed (no, even though I work at Google I had not seen this until now). Street View gives you a 360 degree panoramic view of the chosen location. You can use the mouse to turn around, virtually walk up or down the street, as well as zoom in or out. The picture quality is quite good (particularly in fullscreen mode), generally detailed enough to make out signs and house numbers.
Check out this map of the Embarcadero in San Francisco.
This should be an awesome tool for house / apartment hunting. In the past I have used the Satellite view to get at least a rough idea of the neighborhood, but this adds a whole other dimension and level of detail. You can view houses in the neighborhood, check out the kinds of cars, and virtually stroll down the street to get a feel for the area.
At this point only a few locations in the US are covered, but luckily the Bay Area is one of them (although coverage outside of San Francisco is still spotty). Very nice!