What is your workflow on eBooks? Do you anotate them? Are there any open standards that are useful?

I am slowly getting back into reading, and as a minimalist, I dislike the idea of having (or carrying) books, aside from very special ones, of course.

Is there a nice system to organize (maybe even sync) ebook information; and I mean not only bookmarking where you left, but actually notes, highlights, etc? I'd like it to be pretty "universal", so I don't depend on propietary stuff, and I can retrieve those notes 20 years from now (why else would I want to write some notes, right?).

Also, a bit off-topic for this sub, but... how do you read? E-readers? Tablets? Software choices?