I concur with working from a list and being weight conscious.
I keep a master list which I create a copy of before each trip and whittle down to just the items for that specific trip. Weather, distance, terrain and reason for trip will dictate what I pack.
There are two basic approaches for reducing weight-- bring the lightest weight widgets you can (less weight usually equals more money) and reduce the number of widgets you bring. The second approach probably packs the most bang for the buck (with the exception of things like the tent). While you're camping, pay close attention to all the things you never touch, as well as the things you wish you did bring. The things you don't use will come to the forefront as you hike uphill.
Be sure that your clothing, tent and sleeping bag will keep you warm and dry. Cotton gets a bad rap because it is a poor insulator when wet. But you don't have to spend tons of money on new fleece, just make sure you have something that will keep your cotton clothes dry-- both on you and in the pack. I probably used a Hefty garbage bag as a poncho for several years.
With regards to Jim's "must haves", I wholeheartedly agree that an inflatable ground pad/chair kit combo is worth the weight. Some people swear by water filters, while others use tablets or drops. I love the filter; but it is one of the first things weeded off my list if weight and room are an issue. The stove-- will you want it to simmer, or just boil water? What kind of cookware will you need? Sometimes I just use the coffee pot to boil water. I would say a flashlight is a must have. I like a headlight-- it's hands free. I have also been converted to taking two hiking poles on my trips. In a pinch, I got a cheap pair from Wal-Mart and have been surprised at how well they have held up.
Your equipment list will vary and evolve; and I always enjoy seeing what "systems" others use as well as what "must have" items they bring. A naive and gung ho hiking partner is always a plus. "I'll bring the cotton balls for firestarter and you bring the hatchet. I'll pack a lemon and you bring the skillet."
You shouldn't need much fishing gear-- just what Jim said. Once you have nailed down the dates and destination, I'm sure many on here can give some fly advice.
"Many men go fishing all of their lives without realizing it is not fish they are after." -- Henry David Thoreau