I learned entirely casually...and, other than a couple of cheap toy-grade RC planes, mostly on planes I designed and built myself.
A while back at work, several of my co-workers got into the "Air Hog" style extremely light-weight RC planes which use thrust for control. The hardest part about starting up RC is keeping track of which way the plane is going to turn...when it's going towards you, the stick works opposite.
The Air Hogs were good for learning THAT aspect of RC flying...the planes were designed to take a heck of a lot of punishment.
At that point, I bought a conventional RC setup (brushless electric motor, RC controller, set of servos, etc.) and started designing planes. All were very simple, profile-type with flat airfoils. The ones at the beginning were horrible, but still pretty durable with the depron foam. Never broke a motor or other expensive part until several years into it.
My designs eventually evolved into ~24" span biplanes powered by a Park 250 motor and a LIO battery. They take off at half-power, and can really loaf around in a slight breeze. I built one for a more-experienced buddy, and he really loves it. Been flying it for ~4 years with no major mishaps.
Here's a video that shows how much better pilot he is...and how durable the planes are:
http://www.youtube.com/watch?v=M_3D1ztbvRA
I eventually wrote up some plans for folks who were interested in the design. If you've got Powerpoint or a reader, you can download them at:
http://www.wanttaja.com/rc.ppt
Ron Wanttaja