I use notebooks that consist of a bunch of US Letter sized paper folded in half when I’m gaming and I also have a small box which I carry them in.  The problem is that a standard pathfinder character sheet does not fold in half well, and frankly I’ve never been a fan of the layout for the base D&D 3-3.5 or Pathfinder character sheets.  Enter my centerfold character sheet.  It’s a work in progress but so far I’ve been using it.  It’s 10 pages long for different circumstances but you only need page 1 and 2 for a basic character sheet.

character sheet CF