The folding crate carry looks great and is great at the start but continuous use and it breaks ... both my wife and I used them for various things: I for RPG and carrying my RPG stuff around, she for Primary School to save her back when she had to tote arts and craft etc. around.
After roughly 6 months they both show signs of heavy wear then suddenly mine gave out (one side detached in one corner) it was unsalvageable. A couple of months later hers gave out. I used mine A LOT (every Friday lots of gear - books, battle mats, atmosphere items, paper, pencils, minis, etc).
I currently play at home (lucky me) however one of the alternate DMs uses a travel bag, the kind with a trolley to carry all of his books ... seems to have held up for more than a year now. And it doubles as a travel bag
I have a large collection of bags - okay so it might be an addiction

But the ones I recommend are:
* a light canvas messenger bag for just a PHB, Relevant Splat Books, character sheet, dice, pencils etc if I am playing.
* a
Crumpler (tm) messenger for heavy duty lugging around (17" laptop). They have heaps of bags, heavy duty canvas, some are slash resistant. I've had mine for 7 years and nary any damage.
One thing to note that although I don't like the pricing, having the PDF of a book is a deity send if it is fully indexed and searchable. A single laptop is better than a lot of books. You can run a number of character sheet applications (or a text file) for your character, you can search your documents (pre-opened at home for speed), you can have downloaded utilities for everything. This would reduce your carrying requirements for books at least to a small footprint.
Which reminds me: whatever happened to the small price for PDFs 4th edition if you have a copy of the book?
D