There are quite a few companies that make good quality "tactical" backpacks and gear. None of them are cheap... and there are many knockoffs and other crap on the market.
Some of the good companies are:
http://www.tacticaltailor.com/http://www.eagleindustries.com/http://www.atstacticalgear.com/http://www.specopsbrand.com/http://www.mysteryranch.com/militaryhttp://www.camelbak.com/Military-Tactical/http://www.first-spear.com/http://www.blueforcegear.com/This is no where near an all inclusive list, but these are all companies whose products I have used in the past or currently use and I trust them all.
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"Trust in God --and press-check. You cannot ignore danger and call it faith." -Duke