Not to take anything away from many of the quality courses available, but CS212 is probably the single best course on Udacity, Coursera and EdX combined (I've probably gone through about 20 courses on all these platforms so far).
Watching Peter Norvig's solutions is a mind-expanding experience and I learned a ton from watching this course, several times over, and working through the problems.
The videos are well paced, with lots of quizes in between, and always include the all-important solutions. Comparing my solutions to Peter Norvig's has been.. illuminating.
The assignments are tough but fair, and solvable based on things you learned in the preceding lessons.
I've been writing Python for years, both professionally and for side-projects, and I loved the style of the code shown in this class. Many educational resources drive you toward the typical over-engineered object oriented approach. While this class shows you beautifully functional Python that you probably didn't even know existed, peeling away all the silly layers of abstraction and getting down to the heart of each problem in a clear and direct manner, building up amazingly clean, testable and flexible solutions.
If your first thought when you face a programming problem is to start writing a class then you'll probably be in for a shock. Otherwise I think you should be in for a real treat, as you get to watch a true master show you how to write great code.
Big thank you to Peter Norvig for putting it together and I really hope he decides to offer another class soon. In the meantime I'll keep re-watching the videos from this class and finding new nuggets of awesomeness that are so plentiful within.