I taught myself TI-Basic in the 7th grade. Then when I was really fluent in it and started hitting its limits around the 9th grade (I was mostly interesting in writing real time games), I picked up z80 assembly. Later (10th grade) I wanted to write programs on my computer, I installed Linux and learned C (not that they're related, but the hacker world really intrigued me. It also means that I spent my first "real" programming years as a member of the broad Linux community; I even submitted patches to large FOSS projects like Gnome, which still shapes me as an engineer to this day).
Then in university we used Ada for algorithms/application programming the first semester (partly because I'm French, and French professors love the fact that Ada is French; and partly for the reasons parent poster mentioned), before transitioning to C (at first for Unix programming, and then more general programming), and finally doing C++/Java in our final year (we also had a few domain specific classes where we used a different language: SQL for databases, assembly for electrical engineering, PHP for webdev, etc.).
I really like the progression I followed, as I feel like it was logically consistent, exposed me to a lot of different aspects of computer science, and forged me into a fairly solid programmer. I've tutored students whose first language was Java, and their mental model of programming/computer science was a big mess. The best of them figured things out a year or so in, but a lot of them remained confused throughout their college years.
Now I volunteer with a program that teaches kids how to program, and we use Ruby. I think Ruby/Python are great for giving beginners a taste of programming; and it's enough for the kids who don't fall in love with it. But with the kids for whom programming just clicks and is clearly going to be their field of predilection as a teenarger/college student, I'm starting to believe that C (ideally on an Unix system) is the way to go.