"The only problem is that, unless you really do something outstanding to prove that you know the material, its not something you can put on an application/resume."

Which is why the Education industry is really the Accreditation industry.

It depends on what you're learning.

I wouldn't want to waste my time on a class that just teaches you how to use Hadoop. On the other hand, there are some topics that I'd have a much harder time believing can be treated well outside a classroom setting. Classes that deal with softer skills such as project management strategy or research design really seem to benefit quite a bit from the group learning environment. You could certainly learn them other ways, but probably more slowly. If you're trying to build a career there's an opportunity cost there.

It is okay for CS classes, but not for chemistry...

I think a difficulty with this approach is that a textbook often contains more information than you actually need. In that regard a class is better because you have more guidance. The best way is possibly to look through the syllabi of classes at various top universities to get an idea of what is important.

Also, a textbook doesn't have everything you need, and knowledge and technology change; there's no substitute for a human with expertise.