My daysack is a black colored Fire Pack made by Apocalypse Design which is a very small but super hard core gear company in Fairbanks Alaska. I have used the bag for 8 years and its about as good as the day I got it. I had them sew some extra clips and reinforcements when I got the bag which was overkill but I'm glad I did it as I have never had a failure outside of one plastic clip breaking but it was not load bearing.
Their gear is far from inexpensive but I have had multiple gear failures with other makers, their gear I believe in 100% and find it to be of a tremendous value.
http://www.akgear.com/index.htm
For going into the field I have a original Bull Pacs aluminum frame. Its great because you can tie any canvas sack, bag or tarp to it with parachute cord. Then after you get to your base camp, you can use the frame to haul fire wood, I have hauled five gallon cans of fuel, five gallon cans of drinking water, and more than I can even remember, If you can tie it on there and get it on your back that frame will haul it. I need to make a new bag but the frame is 100% after 8 years and I got it second hand. Here are some pictures from the company website but I will try to get some personal pictures loaded up soon.
Oh yea one other thing is you can pack two bags or more, use the frame to haul one into camp, then come back to the road, airstrip, raft, and haul the second or as many as you like depending on what your gear load is. I have also just tied my daysack to it with a sleeping, tarp and bow saw then taken off, worked like a charm.
I used in the past the Alice Pack, a very nice internal frame North Face for five years till it starting shredding, and a 70s style Camp trails Frame Pack which also shredded. I liked them all but the setup I have now with a frame and separate pack is the most modular, the hardest working, and the best overall design by far, at least for me. One thing I try to avoid with any pack is zippers, they are always the first to fail.
http://bullpacs.com/