I haven't hiked in the desert, but sometime I hike ridges and the like were water sources are scarce or far a way. I use my 3 liter camel Pack (I thought it was light, little did I know! :)) And I usually carry a plastic 1 liter water bottler for mixed drinks and the like. I also always carry a metal water bottle, usually somewhere around a liter also. If I go for a day hike or go exploring I will always take at least the metal container, that way if something goes wrong or I miss place my camp I will have some way to boil water. Don't forget the lighter too!! Rubbing sticks together to make fire is a VERY hard process.

Wolfman