New research published in the journal Psychological Science shows that students who take notes by hand remember more information. Even though students were able to write more when using a laptop they remembered less of the information than students who took notes by hand. The authors think this happens because taking notes by hand forces you to process the information rather than simply copying everything verbatim.
For an overview of the research, see this more extensive post by Scientific American.
Here is the original research article. (Note: you should have access to this journal when viewing it from St. Bonaventure University)