I may use all kind of technologies to manage my data but I still always keep a primitive notebook+pen set on my desk. You can say that there are things that are just more easy to do with a notebook, and that's true, but in addition, this notebook helps me to think. I sometimes only need to grab my notebook and pen without any scribbling and I already get into "thinking mode", it's like the pretence of writing signals to my brain that it's time to work.
When I think about it, I actually can't perform heavy thinking without a pen in my hand. I remember last year when I had an Advanced Algorithms course, the homework weren't so hard so most of the questions I solved with a pen and a blank paper in my hand, whenever I tried to give up the pen it just felt awkward.
Another example is that I can't remember some fact I always try to think of a situation in which I used this fact and it often helps (in other cases I just can't remember no matter what, but that's another issue).
