Your target weight is a very personal quest. Your needs will be different then everyone else's, but this is a great place for ideas and feedback. Your gear list will also evolve over time, so be patient and flexible as you collect gear (it can become a hobby in itself).
Are you carrying only one flashlight between the two of you? Headlamps are awesome! One water bladder between the two of you? Raingear? Pack cover or waterproof stuffsacks for your sleeping bag? Bear bagging rope? One toothbrush?
If this is a gear list for two, be very clear on how many of each item you'll have.
Sierra Designs Lightning--substitute most other tarptent style shelters and save 1.5 pounds or more. Check out Tarptent, Six Moon Designs, Mountain Laurel Designs. All have excellent products and reputation.
Big Agnes pads--I use the BA Insulated Air Core, but am switching to the Neoair for summer use. BA are great pads, but there are lighter options.
Marmot Trestles--to what rating? There are many options of sleeping bags under 3 pounds.
Kitchen--try paring down the kitchen to absolute essentials. I get by just fine with a Snow Peak 450 Titanium Mug, Spork, and stove. With an alcohol stove, my entire kitchen is under 4 ounces. I only boil water so I just heat up the water in my mug, and either add freeze dried food or rehydratable foods. But, that's just my system.
Water-- your three Liter bladder at 7 ounces is probably a Camelbak? Try Platypus bladders. Their 2 L Hoser w/hose is 3.75 ounces, plus a 1 L collabsible bottle is another 1.12 ounces. Each of you can carry that setup, weighing 5 ounces each. In my experience, unless you know there'll be a shortage of water along your trip, that should be plenty of water storage.
Filter--First Need will purify your water, which pretty much every other filter WONT do, but its heavy. Try a lighter, more traditional filter with some Micropur tabs to purify. I made my own filter out of a Katadyn filter cartridge and a wide mouth Nalgene Cantene that weighs 5 ounces. That has a .3 micron rating, which takes care of everything except viruses. Can do a liter every 2 minutes. If I really question the water, in go a couple of Micropur tabs!
Survival Kit- Your first aid kit shouldn't need to be more than 4 ounces. Add in toiletries, and it shouldn't really need to be above 6-7 ounces. Check others' gear lists for ideas.
Packtowel--unneeded or lighter options.
Trowel--use a tent stake or stick or rock instead
For EVERY piece of gear, make sure it is absolutely necessary to take (ok, most of us have a creature comfort or two, like a nice pillow, heavy photography gear, etc...) If you don't absolutely need it, then don't take it. Next, look at every piece of gear you have, and search out lighter options. Research, analyze, weigh, repeat. If you don't have a kitchen or postal scale, this is a very important investment in the quest to lighten up! Essential even!
Depending upon financial means, most of the stuff you have can be replaced by simply buying lighter gear. You can also make some of your own gear, like a new windscreen. 2 oz for a windscreen seems very heavy.
These are just some suggestions, and I'm sure some more of BPL's finest will be along to add their ideas! Good luck!!