I don't grow any bonsai (yet) but my friend has at least 20 or so different kinds in his backyard. My favorite (by far) was the cypress tree. I just find them some gorgeous to begin with, and a little one so cute! He also has a crape myrtle, some kind of lime (and yes it does get tiny little limes, so maybe a key lime).
I can't wait till I can try it one day, so thank you for all the great info.