Just a few thoughts.
A gallon of USA water weighs 8.35 pounds while a Canadian water weighs 10 pounds.
I usually estimate a US quart as a litre (0.946352946), or 1,000 grams (2.2 pounds). Water is heavy no matter how you carry it and resupply is a definite must.
Consider the weight of a gallon of water again. If you are supplying all needs from you pack one gallon a day is prohibitive to pack.
This means water treatment usually must be available if you are going for more than a day. The weight of the water soon overides the weight of the containers.

I have carried water in a lot of different ways and they all have advantages as well as disadvantages.
Metal has an advantage as far as heating water right in the container.
Plastic wins on cost.
Weights between plastic and metal are usually comparable. Metal can be a lot thinner than plastic to do the same job.
What you sacrifice for weight saving is usually balanced by what you lose in durability.

Over the years the most common problem I have had has been leaky caps.
This has been far more common than leaking seams or holes. Even the Nalgene bottles are not immune to leaky caps.

Water bags like camel back bladders and bota bags have the advantage of compressing as you empty them.
Air might not weigh much but empty containers still have bulk.

I like carrying a stainless steel thermos (Thermos brand are reasonably light) which lets me carry hot or cold and is usually enough for a day.
1 litre Plastic pop bottles are my next choice based on cost and durability.
In hot weather freezing water in plastic bottles is good. It usually melts just fast enough to supply you with cold water all day.
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Blanket/sleeping bag depends on time of year and the rest of your system.
I find wool too heavy for the pack. Good synthetic bags work for me. If you use the compression sack right you can get them down fairly small.
I have a Woods 5 star that weighs about 5 lbs, but that is far too heavy and bulky of a bag except during deep winter. It almost requires a pack just for it.

I like down for packing but hate it for being vulnerable to wet, so I tend to used medium weight bags filled with Polartech II insulation (or similar).
I find the problem with sleeping pads to be bigger than with the cover though. You need at least 2x as much insulation under you as over you. This is even true if you are sleeping in a hammock or cot.
Air pads risk puncture and compression making them useless.
Ensolite (blue foam) does not compress well so you carry a lot of air in your pack.
It certainly helps to pile leaves and other insulation for a bed but it is not always possible to find dry bedding material.
Hopefully somebody will find a way around this problem.

"A gallon of USA water weighs 8.35 pounds while a Canadian water weighs 10 pounds."

It doesn't make sense to me. There's something I am not getting. Do Canadians use Imperial gallons and therefore a Canadian gallon weighs more? Can you explain?

Canadian Dideuterium monoxide is heavier than the more commonly used Dihydrogen monoxide found in the USA.

http://www.youtube.com/watch?v=hzLs60ZaNW4

http://www.youtube.com/watch?v=YYInVraBe7s

Replacing the Canadian Dideuterium monoxide ice with the more cost effective American Dihydrogen monoxide could even be a solution to save the Polar Bears (due to the global warming) as the lighter American Dihydrogen monoxide ice floats better in the Antarctic Ocean meaning that there is more room for each Polar Bear.

Just two weeks ago, I hiked to an overnight destination, 22 miles round trip, and I started out well hydrated (sloshing, really) with 4 liters of water in my pack because I was not sure of the water source at my destination. Total pack weight was about 3 pounds, a tad heavy, but not unreasonable. I was correct in carrying that amount; no supplementary water was available. I returned with one half liter remaining. Conditions for this trip were ideal - cool and pleasant.

I have often gone out in warmer conditions (southern Arizona deserts on SAR operations) carrying 1.5 to 2 gallons of water when I expected to reach a reliable water source by sundown. You carry what you must to survive in the ambient conditions. At least with water your carry weight declines during the excursion.

A poncho liner and a poncho - GI issue- are a good enough substitute for a sleeping bag. Even better is two poncho liners and a poncho.

The leaky cap is or was a real issue for me and i used super glue to glue a sealant into it and i had my full weight on it and no hissing!!

I have an esbit stove i use to boil water in my canteen cup and it works surprisingly quick. i prefer using trioxane because it lights quickly and in a survival situation, that would be alot better. although they are easily ruined due to oxygen exposure. I need to get a military poncho, i will try to with B-day money. I also carry 10 KATADYN MP1 tablets in my canteen holder. so, i can boil or purify any water i find.

I'll bet you would really like a Trangia alcohol stove. They have been standard issue in the Swedish Army for many years - absolutely foolproof and easy to ignite and use. I used one routinely in SAR because of these characteristics.

I just compared trioxane and hexamine/esbit tabs in my esbit and tried to boil 2/3 of a canteen of water in 32 degree temps and neither got the water boiling (i didnt use a wind guard) any way the trioxane left less of a mess and got the water 37 degrees hotter in half the time! i burnt the whole tablet on both and the troixane burnt for 6 min. and the esbit for 11. either way, the trioxane chipped right off and the esbit... real pain! trioxane wins my vote! it even cleaned off some of the soot from the esbit!

Yes, you got it exactly, sorry for wording it so poorly.
That is why the US quart is so close to a litre in size while ours were bigger.
Remember that your moonshiners used to call a quart of whiskey a fifth. That was because the smugglers were buying Canadian whiskey in Imperial gallons but selling it in American quarts that come out very close to one fifth of an Imperial gallon
Now that we have gone metric almost everything is in litres but we still get old measurements made in gallons, quarts and cups and it is one of the things we need to watch out on.
The difference messes up recipes for cooks too if they are not careful.