I can't remember when I actually used a scrollbar for scrolling. I instead scroll with two fingers on the trackpad, or with arrow keys.
So for me traditional scrollbars are a waste of space. But I still like to have an indication of where I am in the document, which is what almost every mobile platform out there does.
Here is an example how they redid scrollbars in latest Ubuntu: http://www.markshuttleworth.com/archives/615