They're pretty important, I think.
I've always made notes and it was something from year seven study skills classes that I learned. I think it's important to rewrite things in your own words because it reinforces your learning and personally, when I finish a set of notes, and punch holes through them and sort them into folders I get this immense sense of satisfaction. /slightexaggeration.
I've done it for every subject this year and it's been working out well. I would find it rather annoying to lug around textbooks with highlighted sections and whatnot, and with your own notes everything is there, in front of you with easy reference so you don't need to keep flicking back and forth in those massive textbooks. And as you said, for the sciences if you answer dot points directly from the syllabus it seems more efficient, and it is because not only do you have the benefit of checking things off as you've summarised but also a clear indication of what is to come in your exams.
As for the humanities - well I do Modern history and it involves quite a bit of essay/analytical writing so if I have my notes in front of me, I know exactly where my info is and there is no need to tediously sift through textbook after textbook for relevant info. I can see the benefit of having notes for eco, bus and legal because, for example, if you condensed all the statistics relevant to your topics into one page then that saves a lot of time and that time spent head scratching could have been used doing something more useful... say, surfing BOS? hahahaha.
Just my opinion. But they're pretty central to my learning... I use Word by the way, but sometimes I'll summarise my notes even further using my poor, poor hand.
