Naw seriously,,, athink y ecant take enough...and it depends on what terain yer covering... maybe water might be the best thing fur ye tae carry in the middle o the desert, but a think on general touring...some spares tae get ye to the next safe place,,, wid be tyre weld... some tools. most of the stuff otheres have recomended... but ad say a good lenth of Nylon Tie strap maybe around 3/4 mts of it fur tae use as a tow rope fur the worst scenario it can easily be rolled up in yer pack....

I would say the most important thing to take on a long journey is a camel back.

http://www.wiggle.co.uk/images/camelbak%20waterbak.jpg