- Beer Can Racer
Tactical racing app, much like a held-held GPS but with racing specific features. Excellent, but still a work in progress. - EarthNC
Display of NOAA raster marine charts. Excellent, but still a work in progress. - Marine Traffic
Displays real-time data for (mostly commercial) vessels with AIS. Excellent, but still a work in progress, try the mobile website as well. - Tide Prediction
Best of the (mostly mediocre) tide apps for Android.
- NDBC mobile (real time data from buoys)
- NOAA mobile (weather related information)
- PORTS SF text screen (real time data for San Francisco Bay)
Nexus S, pure Android, best smartphone for my needs.