Web mapping is a substantial way for users to explore data on a site. More and more users are comfortable using a web mapping interface thanks to mostly the work of Google Maps. This means that you can have more confidence in your audience's ability to use a map to find relevant data.
"Google Maps are like stock photography". We are past the point of just embedding a Google Map into a site and putting a few red markers on it. We can do so much more that will ensure that your geographical visualizations do not create such a huge break from the design of your site.
There are a number of ways out of the box with modules, such as the Drupal Openlayers module, that will allow you to easily create a map that actually fits into your site. Then, by utilizing outside services like MapBox and Cloudmade, you have much more control over tile sets you use. And you can even take it further by looking into rendering your own tile sets and customizing the markers and graphics so you have the exact look you want for your site.
Ideas, inspirations, collaborations, and thoughts come in part from AndrewL's past presentations: Don't Let Maps Cramp Your Style.
Video at archive.org.
The people that will get the most out of this session are people who are responsible for building the visual communication of a site. Making your maps look good can span from site building to theming to very technical tile rendering.