Well, I've come to find over the past while that the maxpedition bag is a) not waterproof at all b) cannot carry a whole lot of extra odds n' ends. To that end, I picked up a bag on sale at REI. It was normally around $100, but it went on sale for $39.99 for Christmas, so I got it and a hydration pack for it. I also vacuum packed a shift of clothes (jeans, multiple socks, t-shirt, tennis shoes) since I would probably initially be in my office clothes. Walking any distance in hard shoes, dockers, and a polo probably wouldn't be the best way to go.
Here it is repacked with a few other extra items next to the maxpedition bag.
I've repacked it a couple of ways with extra medical stuff and a few more food/water items. I'm finding that even though it carries better, it doesn't seem to have enough pocketed areas to separate stuff out. I put everything in baggies and such to keep it all organized, but it just....I dunno....meh...doesn't 'fit up' as well as the maxpedition did. That bag had bunches of separate compartments. Got me some more pondering to do, I suppose.