Stumbled across OpenStreetMap while checking out an offline map reader for the iPhone. Before opening the site, I was dubious that a wiki would work well for a map as well as it would for text, but I was wrong.
Surprisingly, there’s more detail on OSM than Google’s offering in the region I was interested in. (My parents are going overseas soon for a wedding, hence the sudden interest in Croatia.)
OSM also excels at showing administrative boundaries I usually have to open Google Earth for (and even then, they’re hard to read due to the imagery). Now I know why my friend’s address is in Menlo Park!