well, my opinion is that the solution to this problem is not to teach people how to use the terminal. I see the terminal as somekind of "easy access" programmer's button. I know there are HUGE differences, but, as with the programmers button, somebody who doesn't know about it shouldn't use AND shouldn't be tought to use it. Apple has to fix these problems! I noticed that "clean" installs of 10.1.x don't tend to have these problems, but people who are using and updating since 10.0.x still have them. I decided to completely switch to "root" in 10.0.1, and haven't had any problems. But "normal" users shouldn't be "enlightened" to get Superuser. They can destroy too much with it! Forget one argument or mistype an argument in a command like "rm -df /folder" and your HDD is erased faster than you can imagine! Apple should simply fix the problem and MAYBE introduce some kind of Admin-Clean-Up tool, you know, where you have a button to empty the trash regardless of what's in it etc.
But leave the Terminal to the people who know how to use the terminal. My ex-boss doesn't know Jack about the Terminal but feels "cool" when he uses some commands he red on the net, he feels like a "l33d hAxOr", and he screwed up his TiBook more than once.
That's MHO.
Update: I just red my post again and noticed that it might sound a bit different as it was intended. I don't wanna say that you shoulnd't teach someone how to use the Terminal, no, I encourage people to learn how to control their system on terminal-level, I just think Apple as a software engineer shouldn't rely on this solution.