For a freeware model the Ryan Navion is nice and easy on the eye, and good for a spot of Low 'n Slow whilst checking out the scenery below.
90% of my flying these days is in the bigger birds, mainly the PMDG B737-800/900.
When I do fly low, my absolute favourite to take for a spin is the little Realair Duke B60.
http://www.realairsimulations.com/dukeb ... 2_overview