I find notes useful in putting together the many study guides, textbooks, articles, handouts the teacher and i get/give in ONE place. I also always ensure my notes are smaller than the chapter, and that its simplified. I figure, come exam time, i just re-read the notes, and not the textbooks.
This all depends on the subject too, e.g. maths=no notes for me, just excserises and tests, english- reading books, essays etc, i find note writing a great revision tool, because it forces me to read the textbook, and i'm re-writing it on computer, than reading them, so its THREE revision techqniues in one.
I absolutely HATE anything visual which attempts to make me revise/learn. In school we are forced to do mind maps, and diagrams sometimes to define key concept,s or summarise what we learnt. But it's useless for people who are not visual thinkers. As a result, i never end up looking at these plain, simple and messy drawings/diagrams, and therefore it doesn't help. I really do wish i was a visual person, because you are right, every study guide etc recommend mind-maps, but i find it difficult to see how i can put a WHOLE course onto pictures, b/coz then in a few month's you'll be like "what does this picture mean" in other words you cant expand on an idea, without writing it.