Somewhere down the line I got sucked into the moleskine craze. It is a good notebook, and I often get complimented on the particular paper/pencil combo (I use a Zebra M-301 mechanical pencil).
I it for joting down notes, ideas, things to do, whatever. Lately, I've also started drawing in them.
Also between the covers: a few loose index cards, some emergancy cash, and dental floss. Not shown: contact info in case I lose it, stickers, pictures, and whatever else I see fit.