This thread finally got me to register.....
Background: I thru hiked the PCT in 2006 (all 2665 miles of it). In years prior to that, I hiked the Washington Section over several years. Since, many a trip under my belt.
Re water and water containers: Gatorade / soda / 1 liter / 2 liter bottles are perfect choices. Just think, the water bottle costs $1.49 and comes free with a liter or two of the beverage of your choice. They're practically indestructible. I still use the same bottles I carried on my hike over 6 years ago. For water treatment, only do iodine IF you also carry vitamin C tabs. Wait 15-20 minutes after dropping in the iodine and THEN put in a crushed vitamin C to neutralize the nasty taste. Filters are heavy and expensive. Use Aquamira for a reasonable tasting 2 part chlorine dioxide treatment (what I used on the thru hike).
Re what Soners said about quits: Incorrect. Lots of people use quilts on the PCT. You spend weeks at altitude in the high Sierra (Forrester Pass tops out at 13,000+ feet, for example, with mile upon mile above 10k). A properly sized quilt is more than adequate for 3 season hiking. Thru hikers use quilts because they're lighter than sleeping bags, not heavier, for a given warmth. Most guys carry 30 degree rated bags / quilts and most gals use 15 degree ratings. I carried a 30, but was fine to 23 degrees (tested at home pre hike, that was lower comfort level - survival level would be significantly lower) since a bag / quilt is part of a sleeping SYSTEM. That system is the bag / quilt, pad and the clothes you carry / wear.
Skip the liner - little warmth for the weight. Ask yourself: How much warmth does one thin layer of silk provide? Answer - not much. Use the 7 ounces for a fleece, or more down in your bag or quilt. If it's a warm night, unzip the bag and leave an arm or leg out, or your torso uncovered. If it's cold, wear your fleece or down puffy jacket to bed.
If you buy a 0 degree synthetic, you'll be lugging around an over weight, bulky, over kill piece of gear. Compare and contrast the specs on 0 degree synthetic to 15 degree down.
As MMM says, buy QUALITY. When it comes to bags / quilts, that means either make the quilt yourself with 800 to 900 fill down, or buy a very high quality manufactured bag or quilt from Feathered Friends, Western Mountaineering, Marmot or similar. Stick to down - it's far warmer per unit weight than synthetic. Go at least for 800 fill, if not 850 or 900 (650 / 700 down is garbage, suitable only for rectangular bags used in car camp state parks). Down also packs smaller, which allows for a smaller, lighter pack. Properly cared for, a high quality down bag will last many, many years. The bag I carried on the thru hike in 2006 also had 500+ miles on it before hand (bought in 2002), and it's STILL nearly as good as the day I bought it 10+ years ago. Down bags / quilts MUST be stored uncompressed, preferably hung up in a closet, or in a large cotton bag that comes with the higher quality bags. That's value. Buy it once, buy it RIGHT and it'll last you forever.
If you buy a used bag, insure it hasn't been stored compressed in a stuff sack - lay it out. If the seller pulls it out of a stuff sack in front of you, thank them and leave. The bag should "fluff" up in a few minutes or already be fluffed up - if not, pass on it and go on to your next choice.
Tarp tent is a great product - I've been using one since 2003. It's hard to go wrong with anything they offer. Also check out 6 Moon's Designs and Gossamer Gear for excellent cottage manufacturers of light (and in many cases) reasonably priced alternatives to the REI / MEC / big retail shelters.
Rain gear: Being from Washington, I take rain protection seriously. One word: Poncho. Cheaper, lighter and more effective than so called "breathable" water proof 300 buck parkas. A poncho also covers your pack as well. I was the only one in my bunch using a poncho on the thru hike, and was the only one to stay dry after 2 solid days of rain here in Washington.
DIY on the stove is a great option for cheap and light: There are many alcohol burners out there - "Pepsi" stove, Fallingwater, etc. Note that about the only drawback to alcohol stoves is that you generally can't turn 'em off once lit (some designs lend themselves to a snuffer to put them out). If you accidentally knock it over, you'll spill burning alcohol all over, possibly igniting a forest fire (it's happened on the PCT before). Be sure to clear a good area down to bare mineral soil and be careful to not knock it over.