For a two week camping tour I reckon on 13kg, which is two smallish panniers, and tent + sleeping bag on top. This would include a small amount of food, how much more depends a lot on how remote.
If you have books, ipod, more than one change of clothes (excluding a warm layer and waterproofs) then you probably have too much. A hotel bar of soap does for shaving, shampooing and clothes washing...etc etc.
The lighter you get it, the easier it is, and you stress the bike less. Over-pack and you start running into problems like broken spokes.