Camping in colder climates or near glaciers is interesting when packing. Gryllus is right, most of the bag is clothing, tent and sleeping gear. Very little of the weight in my pack is the food. I did a couple of 3-4 day treks in the rockies in Alberta this summer, and had more than enough layers to keep me warm at night and early morning.
For dayhikes/really long runs, I picked up a North Face Enduro 13 hydration pack. It's got a slot for a 1.5 L bladder, with room for raingear/extra footwear in the pack. It also has a waistband that has water bottle holders and two roomy pockets for snacks. It's a killer pack for a dayhike, and I got it especially for when I run the Skyline trail in a couple of summers. 45k of beautiful trail, and I can't wait to get on the trailhead and run it. Right now I've got an old nalgene bladder in it that has served me well over the last 6 years. It just doesn't die, so I'll keep using it. The bottles are surprisingly easy to access on the run, and there are cinch straps so I could put bear spray in there instead of one of the bottles. The only downsize is the chest harness is a little on the small size, and takes a little bit of tinkering to get it to fit just right. If you've got a big chest, it'll be tough to get it to work. Once it's on though, it doesn't move at all, and the bladder sits in the small of your back. It's 100 times better than the old nalgene bag that I had before.
Here's the pack:
http://eu.thenorthface.com/tnf-eu-en/enduro-13-hydration-pack.html?tracking=231e093e10c0a0dac460615448c244b7
