Google are stopping development on Google Notebook, which I had used for a long time. I liked the fact that I could integrate all my tools for research on my Google page. Recently though, I had switched my organising from Notebook and Delicious to Evernote, which is much more visual and versatile. I even transferred my Delicious bookmarks to a folder there, and things are much clearer.
Here is a good post on how to use Evernote for students.