For the last couple of years I've been writing a NMEA logger program (Windows), that captures, logs, plays, displays (etc) NMEA 0812 data. It provides dial displays of most data, as well as AIS display/alarm, depth alarm, MOB alarm, stripcharts, etc. I took it to Hawaii and back during the '08 Pac Cup and have been bugfixing and feature-creeping since then. IMHO, it's pretty useful.
You are welcome to use it for free, and I would welcome any constructive comments. I do not intend to add chart-display. The screen is optimized for the (tiny, low power) EeePc, but it works fine on larger computers.
In particular, I would appreciate any NMEA capture files you might generate, so I can test it on other people's data.
Here is the main screen:
And the AIS screen:
If this sounds interesting, you can read more, and get the setup program here:
NavMonPc
I have no intention to sell this program, and any support will depend on my attitude at the time. I guarantee nothing!