I love Springpad.
Right now, I'm keeping a notebook for Next Actions, tagged by context. In the same color, I have a someday maybe notebook, a waiting-on notebook, a problems to work on notebook, and a shopping list notebook.
In a different color, I have a notebook for important information about my apartment and roommates
In color 3, I keep a notebook for general cooking technique and one just for recipes, the recipes are tagged by course.
In color 4, I have notebooks for specific projects and their support materials.
And finally in color 5, I have one notebook a piece for all my hobbies.
Hopefully this gives you some ideas, but remember that I didn't set all this up out of the gate. It just evolved one notebook at a time as I needed them, and the groupings and usages emerged out of that.