That's a hard question... I learned with an Exa 1b (very primitive SLR without light meter) and 50mm lens and it tought me a lot. Firstly, you need to really understand shutter/aperture/ISO with a camera like that, secondly it tought me to properly compose an image before taking the photo and not take 100 photos and select the single one that might be ok.
However, if I needed to teach someone photography today, I'd use digital. Being able to view the pictures right away can be very useful. For the very beginning (until the exposure is properly understood), I'd set it to manual exposure and probably even use an external light meter. Most people who only know automatic cameras don't understand the basics, though they're very important. A 1000+$ camera is no good when you have to ask "how do I make the background blurry?" or "why do all the pictures look shaky?"
If you want to learn something you need think clearly and it's a very bad idea to let a computer do all the thinking for you.
Later on, the automatic modes are very useful (I shoot mostly in aperture priority or program mode with Canon EOS), but they're no good, when you don't understand what they do.
The best method would probably be large format with polaroid, but that's got little to do with the kind of "mobile" photography that most people are into. It combines the completely manual aspect with being able to see the results right away, but lacks the possibility for experiments, unless you have all the time and money in the world.
Learning photography is completely different from being a professional photographer. If you shoot weddings, you probably know how to use a camera and what all the settings do. It's the results that count. As a beginner, the results don't really matter, but it's about understanding the technology.
On the topic of chimping and polaroid: There's a difference between deciding "I need a preview, because the lighting situation is rather difficult" and looking at the display after every shot to decide if you'll keep an image, probably missing a dozen good opportunities while doing so. With my d*g*tal camera, I turned off the automatic review screen, so I'm not even tempted to do it. When I'm not sure about an exposure, I can still look, but it's not like the involuntary habit of "chimping"