I have been using this pack and have been very happy with it:
http://www.cabelas.com/cabelas/en/te...770&hasJS=true
It is a bit larger than I thought (5,300 ci) as well as heavier (11.25 lbs per manufacturer). With the exception of "emergency gear", everything I take is used on a daily basis. I like the larger pack because everything except the gallon milk container fits inside which is VERY convenient when having to deal with weather as well as branches that on every step try to grab your pack. The integral rifle holder is nice on trails, but more hassle when bushwacking and I usually "hand carry" the rifle in that situation. If you use a pack with an intergral rifle holder, you should also use one those "rifle socks" for protection (ask me how I know.)
Good luck to everyone hunting this year!