I will go against the majority here and chose the plane I have built and flown most and taught others to fly and that is the Tiny Trainer.
It is so configurable that you can arrive at a field with a pile of components and quickly build a plane you can fly in the prevailing conditions.
Here is a link to some of the different things you can do with a Tiny Trainer BUT the list is no where near complete and the developments have definitely not ended.
https://forum.flitetest.com/index.php?threads/ft-tiny-trainer-mighty-mini.17059/page-6
Sure we all eventually tend to retire our TT and move on to more elaborate builds with greater performance but that still does not detract from the pure enjoyment of hacking into your TT and making your own version!
Some of us are not able to build hundreds of planes and outfit them all with the required electrics and I do not discard any assembly I have purchased until it is irreparably damaged.
I have many planes in my hangar of many sizes and construction materials but it seems I always have a TT to hand ready to try out my latest aerodynamic ideas or research projects. For its performance, resilience, serviceability, simplicity, cost, and its ability to be made into almost any possibly configuration in a very short time I will say that the TT is my favorite!
Have fun!