I tried searching the forum, but I was unable to answer my question.
It was brought up that the spun blow fiberglass economy filters are not quite idea because they let some dirt through that could get to the cooling coil. I guess this could be solved by making sure you have your unit serviced each year so everything is cleaned out.
But what filters out there are a good replacement for these filters? My ideal replacement would not be very restrictive on airflow, be easily available, and reasonably priced.