I have joked around about food, but that is an area that I have made the biggest gains. I have been counting my calories each time and readusting for the next trip. I have been averaging 2600 calories per day. If I were to be out more than 2 nights that number starts to go up a little. The last 2 trips i went home with a pack of oreos. For where I hike that is just about the margin of safety needed. If I lose a pound of body fat in the process, I concider that a bonus. About 50% of the time I don't carry a stove which also removes spork, pot, and fuel.
I also monitor my water very closely. That is the heaviest thing in my pack. I drink a gallon a day so I have to refill my 2 liter platypus twice. If there is a reliable water source every 5 miles or so I will only carry 1 liter. I also camel up before I leave and at water sources.
Since this is HF the rest of the gear is more on subject. I concider my hammock, tarp, quilts, pads, headlamp, raingear, clothes, and sometimes my pack to all be part of my sleep system. It mostly has to do with comfort, but safety has a big roll too. I really don't compromise much on these items. All those items come to about 6 to 9 pounds depending on the weather. I much rather scimp on food and have to resupply then get cold at night. I still only carry the smallest tarp that will keep me dry and the lightest quilt. I use running tights for sleeping and for camp in the morning. I like my 3/4 quilt and prefer it over a lighter pad.
The rest of my pack is just a small first aid kit, toiletries, and maybe a phone, Ipod, and a camera.
I don't understand what people carry to get over 30 pounds, but I know when I started backpacking my pack weighed that much or more.
For the most part I am talking about backpacking and not camping. When I camp I just bring it all.