US Grib- A free GRIB viewer (weather forecast).
Predict Wind– These guys do really awesome weather routing and modeling. Given your boat parameters and conditions just set a destination and it will tell you the best course given weather forecasts for your area. If you’re looking at an Iridium Go! this is a great place to buy the package.
iNavx– Very cool navigation software that includes AIS overlay and instrument display for NMEA data.
Seamantec– Really awesome displays for NMEA data (wind, speed, depth, etc.) from your boat electronics right on your Android, iPad, or laptop.
OpenCpn– An opensource and free charting and route planning application.
Rose Point Navigation– A really user friendly charting and route planning application with NMEA instrument displays and radar overlay for Koden Sitec Radars.