housing info using google map
http://housingmaps.com/
you can search by city and price range, and it will show on google's map.

gas price info using google map
http://www.ahding.com/cheapgas/

crime info for chicago using google map
http://www.chicagocrime.org/map/

crime info for florida using google map
http://www.floridasexualpredator.com/

traffic
http://supergreg.hopto.org/google-yahoo/

flickr photos using google map
http://www.thickey.co.uk/gmaps/