Even though I have no practical need for water/tear proof paper I couldn't resist picking up some Expedition Editions too. They don't hold ink from any of my regular pens very well, so for now they're just to hold, cherish, and wish I had a need for them.
My current obsessive notebook traveling rotation is pictured below.
Always with me are three pocket memo books from Field Notes (a Red Blooded graph paper for notes, and the classic version in plain and graph paper for dodling). Pictured here they're banded with a highlighter and a few UniBall Signo's - my current pen d'jour.
In my messenger back there is always a Moleskine Folio A4 Sketchbook (for doodles and drawing) and two Moleskine Folio Ruled Note Pads (one for writing and one for journaling). Also in my messenger bag at all times is a meshbag with 20-30 various pens and markers (my paper addiction comes second to my pen and marker addiction). Each of those notebooks have a few post-it notes on the inside covers and a few index cards in back. The A4 sketchbook also has a traveling morgue file collection of about 20 pages of random drawing fodder and inspriation.
Seeing that in writing makes it seem even crazier than it already appeared.