For years, I've been a devotee of the little Moleskine journals, small books of nice paper (with lines or grids or nothing at all, depending on your preference), bound in a bit of colored oaktag cardboard.  For some reason, these little notebooks were much handier and always had a space in my pocket or purse, at the ready to take down an odd phone number, a task that had to take place, or an appointment to be transferred onto the "big calendar."  No notepad or spiral bound booklet did the trick: it had to be one of my favorite Moleskine booklets.