A few weeks ago NAVIGON for Windows Phone was updated to version 4.1 which added the MyMaps feature to the navigation app. MyMaps allows you to download only the maps you need. As opposed to downloading the full 1.6gb of maps.
After the update, NAVIGON dropped the price of their U.S. map version down from $49.99 to $29.99. The European version fell from 84.99€ to 59.99€. The sale ends on January 5, 2012 and if you've got some Christmas cash lying around (or a Microsoft Marketplace Gift Card) this is a great deal on a very good Windows Phone navigation app.
Thanks, Tim, for the tip!