RE: First plane after helis
I know what you mean, helis have only scale and sport machines to choose from while planes have all sorts of categories to go: pattern, sport, profile, warbird, scale. But you'll soon find where you like to fly.
Before retiring your 500, you may want to bring it with you when you go flying. I usually will bring a plane or two and my 450 - gives me a chance to even things out a bit. Plus flying my heli really keeps me on my toes!