This is my bag.
This is what I carry in it when I’m running LFR.
From left to right, more or less: three encounters worth of miniatures, a bag of dice, my iPad, a thin notebook, a pouch of beads for marking zones and such, a pouch of pens and pencils, a pouch of dry erase markers, a tube of Alea Tools magnets, a pouch of Alea Tools magnets, a bunch of index cards, a big pouch with the module in it, a big pouch with battlemats in it, and the Rules Compendium.
The big pouches clip to the outside of the bag, which looks goofy but it keeps everything together and safe from rain. All the other pouches have places to clip inside the bag. There’s a pocket inside for the index cards, and another one that fits the tube of magnets very nicely. I’m going to put the rest of the magnets in tubes eventually as well.
It’s all remarkably convenient.