I believe actionscript 3.0 and Flash in general allows you work on a wide variety of projects:
from interactive rich media web interfaces, to interactive video, animation, games, desktop applications, rich internet applications, physical installations, creative and abstract pieces, etc.
It's up to you what you want to do, but I'm guessing if you start with something that motivates you, something that you enjoy working on and learning, it's a sure way forward
and it will make the boring bits more fun, and that's what it should be about: FUN!
It doesn't matter if it's actionscript or something else you want to learn, enjoy learning/challenging yourself and you'll get there faster than you think.
Answer 1.):
With regards to actionscript, based on what you want to do with it, there are a couple of good starts. Let's say you're interested in just the code, not planning to use the Flash IDE much or at all, and your aim to develop great applications. as @David Morrow said, Colin Moock's Essential Actionscript 3.0 is great. Also his guide From the Ground Up is a compressed version of the book.
An easier lecture, but packed with hands-on tips to getting things done in actionscript 3.0 is Rich Shupe's Learning Actionscript 3.0, also from O'Reilly. This might help you get up to speed with project you might have in mind.
Answer 2.) and 3.):
In short you have at least two routes:
- easy/practical start where you learn
by doing small mini projects, but
keep in mind there are gaps to fill
in order to move on to complex
projects
- a 'harder'/more theory based start,
that will cover advanced topics, so
you will ready to take most projects
out there, simple or complex.
Answer 4.):
It also important to keep in mind that there is no substitute for experience! Learn how ever it feels comfortable, but plan time for practicing/writing a lot of code/failing/fixing/repeating. Don't worry about getting things wrong! I don't know any programmer that can write a complex project perfectly from start to finish. Basically all projects out there are the result of this loops of failing/fixing/learning/ if you want to put it this way.
Never be afraid of getting things wrong ! You learn more this way, than getting things right, but not fully understanding why, also, you can discover something new. You can't run
into happy accidents if you don't have accidents at all.
As you progress you will like some things more than others. It is important to try everything when you learn. Knowing what you don't like is just as important as knowing what you like. Don't take everything for granted and form your opinions while learning.
You mentioned peaks. It's great to aim high. As I mentioned earlier, actionscript can be used for so many things, that it's hard to be the best in all areas. Andre Michelle and Joa Ebert for example are very talented developers and have a lot of experience with sound. Chris Georgenes on the other hand is a very talented animator. I wouldn't expect roles to swap anytime soon. If it helps, choose people that are actionscript virtuosos, get inspired by their works, there are plenty of them out there.
HTH,
George