Ditto on REI. I'd also shop LL Bean (free shipping and great return policy) - I have several of their daypacks. The biggest I have is their "white mountain" pack for women. I usually catch them on sale. Excellent quality from a terrific company. The packs all come with a waterproof cover built in.

http://www.llbean.com/llb/shop/1098?nav=ln


As for pockets on the front of the pack, I would simply add accessory bags/pockets. I have these two below from Campmor - super light. My fave of all time is one that was part of LL Bean's fishing bag collection several years ago. I like these accessory pack pockets for storing compass, firesteel, etc - basic survival gear that can then be easily switched out between different backpacks.

Horizontal backpack bag
http://www.campmor.com/outdoor/gear/Product___42223

Vertical backpack bag
http://www.campmor.com/outdoor/gear/Product___42222

I'm also fond of these "belt pouches" because they are light and spacious. And simple.

http://www.bepreparedtosurvive.com/Pouches%20&%20Bags.htm


In my SUV at all times is the LL Bean "Bigelow" pack that received Backpacker magazine's "Editors Choice" award several years running.

For serious non-auto "bugging out" I'd be wearing the Bigelow and putting the White Mountain atop one of my bike trailers that is outfitted with a cargo rack.