Microsoft Bing Maps

Microsoft's answer to Google Maps. While graphically not up to snuff, Microsoft Bing's maps provide unrivaled, rotatable, high-resolution "Bird's eye', 45º Angle aerial photos. Like Google, real-time traffic data is provided for directions as well as Streetside, the equivalent of Street View. The reason for being number one on our list is due to the ability to correctly place Southeastern Wisconsin addresses as well as being able to recognize poorly spelled street names. Google does not.

Google Maps

The online mapping site that everyone knows about. Reasons for being number two are the aforementioned inability to map Southeastern Wisconsin addresses and inaccurately placed points of interest. Despite this, Google Maps does have the best overhead aerial images anywhere.

Here.com

You've probably never heard of Here.com. But, if you've ever noticed the map copyrights of both Google and Microsoft at the bottom of the map, you'll usually see Map Data by Nokia or something to that effect. This is the home of that data - Nokia maps. Like NavTeq and TeleAtlas, they are leaders in providing map data.

OpenStreetMap

OpenStreetMap is like the Wikipedia of maps. Information is added to by its users both by using professional mapping software and its own in-house editor. Everything was built from the ground up without corporate sponsorships or governance. While slightly simple looking, it provides a wealth of information and services to everyone.

MapQuest

Once the almighty God of online maps, it is no more. With the advent of Bing and Google, MapQuest has fallen seriously behind. It uses base data from OpenStreet to populate their maps. Moreover, it uses horrid colors and gaudy icons, giving it the last place on this list.

City of Chicago Open Data

This is the City of Chicago's main data website. You can download and/or browse literally thousands of datasets from crime to street closures to budget information to census data.