> ... with a circular cross section of the Earth I'd expect less debris/area near the poles.

As it turns out, Antarctica is a very productive place to look for meteorites, first because there isn't really a preferred geographical zone for meteorite impacts, and second because of the large, empty ice fields, against which newly fallen meteorites stand out.

One of the most famous meteorite finds of all time, ALH84001, was located by simply driving across the Antarctica landscape and watching for dark objects.

http://en.wikipedia.org/wiki/Allan_Hills_84001