It looks like you and I have pretty similar loads (the documents - not so much. I rarely carry documents, but when I do it is imperative that they remain dry and unwrinkled). I got a plastic fold resistant portfolio at office depot, and both my messenger bags (one skooba for when I need my laptop, one cheapo S&B for when I dont) have document pockets inside them. Also, on the cheapo bag, I bought a can of aerosol water sealant for fabrics at a local camping store - I've been buying the stuff for years and it tends to effectively waterproof almost anything for about 6 months.