I have only one aircraft made by RealAir Simulations, but it is one of my favourites because of the fidelity of the modelling, and is worthy of a place in this list.
It is the Spitfire Mk IX and Mk XIV which is a beloved tail dragger, and a pleasure to fly throughout all phases of flight.
You'll find RealAir Simulations online here.
I love the shape of the wing on this bird. There aren't many aircraft which give such a nice view during the climb as this one does. Amazing history goes with the Spit too, the envy of many a pilot who had to fly some other kind of aircraft.