I use a Mountainsmith Tour also. It claims to hold the 32 ounce bottles and does but not so securely.

That pack is what I call my personal kit and goes with me everywhere. At work, it resides in my truck. If going to the mall, football game, etc, it goes with me.

The pack supplements my edc and contains the following:

Fire:
Stormproof matches
Birthday candles
Cotton balls

Water:
2 12 oz dasani water bottles (fit securely with minimal bulk)
2 potable aqua chlorine tablets
Quart size ziplock bag

Food:
Bag of mixed nuts
Bag of dried cherries
P-38
HD aluminum foil

Shelter:
Tacoma Mtn Storm Shelter
Mylar space blanket
cheapie poncho
25 ft nylon rope
50 ft masonry rope
mini roll duct tape

First aid:
Visine
Sunscreen Wipe
Bugscreen wipe
3 Q-tips

Tools:
SAK - Camper
River rock .5 Watt LED (nice and small)
All leather gloves

Misc:
One 2-way radio
Flash drive with family stuff
Phone card
4 quarters
Monocular
A few diapers (for my kids!)
Butt wipes
2 MRE toilet papers
Trial size alcohol

There might be a couple other items but that is all I can remember. This kit is meant to be supplementary, sort of like the "concentric rings" that the writer for Outdoors Magazine talks about.

The nice thing about this bag is that the waist straps tuck in, so you can use it as a shoulder bag when using hte attachable padded shoulder strap. The shoulder strap can also be used in conjunction with the waist straps for great support and feel without having to buy the optional and dedicated suspenders.

I like the bag but in hindsight it was very expensive (70? for a fanny pack at REI, come on!) and I would probably now make do with something similar but less expensive (like one of the eddie bauers at target or even a wal-mart model).

I question its long-term durability.

Final analysis - Good Option.