I've waited a while before responding to this, to see what others - especially instructors - had to say, and I'm pleased that many people agree with my own thoughts.
I believe that insipient stalls and fully developed stalls are both equally important.
In the normal course of things, if you accidentally put your aircraft close to a stall, it's important to recognise this as early as possible, and recover promptly - hence the importance of the incipient recovery in training.
However, if the proverbial crap does hit the fan, as foxmoth says, you're quite likely to be distracted, and a fully developed stall is not inconceivable. You must be able to control and recover from this.
Knowing instinctively what to do is vital. As www said, try to raise a wing with aileron, and you're dead. (Keef - this is true of every aircraft in a fully developed stall. All modern aircraft are designed so that the outer part of the wing - where the aileron is located - will stall last, thus ensuring that you have a small amount of aileron control before the stall has developed fully, but I would question anyone who recommends that you deliberately take advantage of this safety feature.)
It's also important to actually do the recovery and see what control pressures are required. As "Who has control?" says, if you apply too much rudder, you could well start a spin in the opposite direction. The solution is to practice enough that you know how much rudder pressure is required.
An interesting thing which I learnt during my aerobatic training: if you apply full opposite rudder, and also apply full forward stick before the yaw has been brought under control, the plane is now set up perfectly for an inverted spin. When my instructor tried to get me to do this deliberately, I found it very hard - my instincts told me that it wasn't the right time to push the stick forward. This is a testament to how well the training works - but I can certainly imagine someone who has read the theory but not seen it in practice may panick when faced with a stall and wing-drop, and apply exactly this combination of controls.
And finally - a personal experience which demonstrates how theoretical knowledge is not enough. Fresh out of my 10-hour aerobatic course, I booked one hour of dual in a Pitts S2C. Shortly into the flight, the instructor suggested I try a loop. I hadn't quite got used to the super sensitivity of the controls, and used too much back-pressure. The plane stalled at the top of the loop. I immediately recognised what was happening as a stall. I also knew that I was inverted - hence it must be an inverted stall, so applied the correct controls to recover from an inverted stall - back stick. This, of course, is totally wrong - a stall is only inverted in negative G flight. A loop is a positive G move, so the stall was actually an upright stall, even though the aircraft was in an inverted attitude, and I should have applied forward stick to recover. Of course I knew this on a theorertical level - but applying it in practice, in an unfamiliar situation, is a completely different story. Fortunately, on that occassion, I had a very experienced aerobatic instructor sat in the front seat.
If there's a chance that your aircraft can get into a bad situation, you should know how to avoid that situation, and know how to recover if necessary.
John_tullamarine, I didn't realise that some aircraft don't have their stall investigated during test flying, I'll certainly be checking the POH on new aircraft in future! I love PPRuNe - it's a constant reminder that there's so much more to learn.
Fly safe,
FFF
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