Although I rarely use my GPS, much less than I expected to when I bought it, I find the most useful fields are Track, GS, distance-to-next and time-to-next on the same page.
If the timings on the plog aren't quite working out during the cruise, which can be confirmed by the time-to-next giving a different estimate from the plog, I'll adjust the aircraft heading until the GPS TRK is the same as the plog TRK. The compass/DI then makes it easy to see the drift. Couple that with the groundspeed, it allows me to work out the actual wind vector in flight. Plog revisions made easy, and quicker (in my experience) than using the numbers observed on previous legs.
Someone mentioned that the GPS 3 has E6B functions to do just this, which I never realised. I might have to experiment, provided it doesn't need too much button pushing in the air, as my sausage-like fingers would make a dogs dinner of it.
