I've been thinking about buying myself a GPS for the boat. It seems like something handheld and at least water resistant makes sense. Of course, I've been doing some research online and am considering a Garmin 72H. I don't need mapping. Actually, I don't really even need a GPS it just would be fun.
One of the things that I found while researching that seems like a fun idea is how to optimize your VMG by using a GPS. Here's one article that I thought was great http://www.wingsailor.com/html/vmg___gps.html .