A while ago I stumbled over the Livescribe Pen, a neat device that allows you to write and record simultaneously and connect the audio to your own handwritten notes at the same time.
At the MinD-Akademie last weekend, I sat next to one participant who used the Livescribe Pen to make notes to the presentations and record the speaker at the same time. He has used it for at least two years and still was very enthusiastic about the pen.
I think the pen is not only good for conferences and presentations. There are some situations when you just have too many ideas at the same time and you cannot write fast enough. Writing and explaining what you mean at the same time might allow you to capture more ideas and make sense of them later on. In some situations (e.g., writing lyrics) it might also be beneficial to hum the melody while you write down the text.
In short, it looks like a neat tool for capturing ideas. The only drawback I see is that you have to use special paper, but that seems to be the only drawback.