The way I was taught it, the modes are:

Mode 1 - Ailerons and Throttle on right stick
Elevator and Rudder on left stick

Mode 2 - Ailerons and Elevator on right stick
throttle and rudder on left stick

Mode 3 - "Reverse Mode 1"
Elevator and Rudder on right stick
Ailerons and Throttle on left stick

Mode 4 - "Reverse Mode 2"
Throttle and Rudder on right stick
Ailerons and Elevator on left stick

Single Stick (Maybe we dhould name this Mode 5 ???)

Anyway, my instructor learned to fly RC while he was on a project in Mexico. They fly Mode 1 there.

Although all my flying of my planes is in Mode 1, I instruct new flyers. Since everyone around here wants to fly Mode 2, that is what I teach.

I prefer Mode 1 for my flying because I can be a wee bit sloppy with the movement of the aileron stick and not input any elevator to the plane. Another thing I like is that since elevator is on the same stick as rudder, I am real comfortable using rudder. When teaching new pilots, most of whom are right handed, I find that they tend to want to set the throttle at a comfortable speed and then fly solely right handed. It becomes a real challenge to get them to learn to use their left hand and find out the value of using rudder.

Having said all this, a key to RC flying, as I see it, is learning to use a system that is comfortable for you.