I'll go over a few things that I've forgotten on trips and it has cost me. I'm sure you've got a decent camping list.
You need a GOOD reliable heat source to cook on. Trust me, sometime during that two weeks you're going to want a hot meal. I recommend the MSR whisperlite stoves. The fuel pellets don't work for crap.
You'll probably want a lightweight sleeping mat of some sort. The self inflatable ones are nice, but if you've got a good back you can get by with the super lightweight foam models.
I always recommend a map and compass in case you want to take an off trail hike. Take some time and learn orienteering with a map and compass if you don't know how already.
Water purifier is an ABSOLUTE must. Usually I don't bother with the old school iodine tablets or the new UV systems (they don't work well if the water is kind of murky....honestly I don't think they work very well at all in any case). Invest in a decent hiking filter.
For most backpacking excursions I prefer a head-lamp to a flashlight because it leaves your hands free.
Utility rope (I use 550 cord) is indispensable.
Tent patches of the same fabric and comparable weight to your tent.
Extra shoelaces
GOOD socks. Spend the money, buy the smart wool.
Remember, ounces mean pounds and pounds mean pain. Don't overpack. Really look at each item and ask yourself "In what situation would I use this item" If you don't need it, don't bring it.
The quantity of gear is far less important than the QUALITY of gear that you bring. Backpacking tests your equipment in a way that day-hiking and camping does not. Make sure the stuff you've got will stand up to a week of hard use.
Somewhere around here I've got the total packing list for my last 4 day backpacking trip in Northern California. If you're interested send me a PM and I'll dig it out for you.