I use the older version of this pack. It costs a bit more but the features and comfort of this pack make it well worth the money. I have a tactical pack that I use during my military time and while good a well constructed mountain pack is much better. They are much more comfortable, lighter and have more features. Living in the Rockies I've had it snow and sleet on me in July so I go prepared whether I'm hiking or driving through the mountains. I usually carry:
Complete change of clothes
Fire starting kit(matches, lighter, fire sticks/vasoline cotton balls)
multi tool/knife
gun(I'm a cop so I almost always have one)
high energy food/candy
water/ water filter
whistles
mirror
gps
talk about radio(to keep in touch with partner)
cell phone(may work)
local topo map
jacket/fleece(even in summer)
550 cord
tarp(with 550 cord can make a great shelter)
head lamp/signal flash light
fishing line/hooks/flies
common sense!
As always, have a good pair of boots and let someone know where you are going and your expected return date/time.