I've had a lot of fun this month with the students in my beginning drawing class at Scottsdale Artists School. In addition to our drawing exercises, I've been bringing in classic drawing books and trying to give them as much information as I can so that they can continue their drawing studies on their own. It's only a 4 week course and so of course it's just an introduction to beginning drawing. There's so much to learn.
Just for the record, I think that nearly every method of drawing has its benefits. Sight-size, comparative sizing, quick sketching, copying classical drawings and casts, caricature and cartooning... it's all good. Stretch yourself in all directions!
I've also been directing my students to the Youtube videos posted by Stan Prokopenko at www.proko.com. He has an instructional DVD available from his site (which I haven't yet seen) and so much good information on his videos. He's funny and he's good at what he does - you should take a look.