My results from this past summer
This summer my partner and I went on a road trip all around North America. We started in Juneau, Alaska, went as far south as Carlsbad, New Mexico, drove as far east as Maine and Nova Scotia, then looped back around to the destination in Wisconsin. It was an 11,000-mile trip during which I kept a blog (see rinarledge.com if you like).
I used obdgpslogger on this trip. I had a very high rate of success, mapping most of my trip. In the end I collected a little over 60 megabytes of raw data (obdlogger.db). On my little Acer Aspire, calculating the KML files on a couple dozen "trips" (a thousand miles or so) would take overnite. I just kicked off the process on the whole 60 megabytes, which represents a little over 500 "trips", so I expect it to take about a week to calculate.
The data I collected was interesting. It was cool to see what the data looked like after my engine overheated. It was cool to see that most of the "trips" I took were very short (seconds or minutes long) and very few were long (the longest single trip was short of four hours).
I would offer to post the data but it's too much, I imagine.