If you're looking for a solid navigation app for your Windows Phone, NAVIGON (here's our review) will definitely fit the bill. While it's a feature rich app that downloads its maps to your Windows Phone, it required 1.6gb of storage and costs $49.99 (US version). Yes, I did say required.
NAVIGON has released an updated version (version 4.1) that adds a few features, most notably, MyMaps. MyMaps is a map manager that now allows you to install only the maps you need. If you only need maps for Hawaii, you'll only need 7.6mb of storage. There is an initial download about 300mb in size for system files.
Still, the update can save you a lot of memory. Adding Alabama and Florida (my more commonly used maps) reduced my storage need from 1.6gp to just under 400mb. Along with MyMaps, two additional features are included with the NAVIGON update.
Active Lane Assistant: Displayed in the lower right corner of the map view, the animation reflects the current lane configuration and allows drivers to see ahead. An orange line indicates the way the driver should follow.
Live Weather: Updates and reports current weather conditions along the route and at the destination in real-time. Temperature and weather condition icons appear in the route overview screen before navigation, and three-day forecast is available.
You also have some internal tweaks that optimized positioning performance. All in all the update makes NAVIGON a more attractive choice for your Windows Phone navigation app.
Oh and as an added bonus, NAVIGON is having a Holiday Promotion. From December 15th to January 5th the US version's pricing drops from $49.99 to $29.99 and the European version drops from 84.99€ to 59.99€.
You can find the US version of NAVIGON here and the European version here at the Windows Phone Marketplace.