I have a small Gisteq GPS data logger that I toss in my flight bag. Its about the size of a cell phone, runs for about a week on a charge and I can select how often it polls satellites (from 1 second to almost infinity).
The cool thing is when I plug it into my laptop it paints the complete track on top of google maps which than be be played from start to destination. Its been awesome for cross countries and recently I discovered I can debrief instrument students with it, showing them exactly where they were off course, out of the hold ect.
Push a button and it tags the specific location with date and time so if my camera is synced up I know exactly where I took a pic. If I could hook it up to an online logbook that would be sweet.