I have camelbac bladders in my bags (3 cars = 3 bags), and some type of water filter. I travel 35 miles to work, so that bag has more than the wifes bag or spare bag in the pickup. My main bag has a katadyn pump filter, the other two have life straws of something similar that can go inline with the drinking tube on the bladder. Otherwise they have about the same stuff as mentioned here, plus a rain poncho.