I forgot soap - though it's probably too ordinary to remember. I use the same handmade stuff for washing, shaving, shampoo and laundry - and as it's solid, there's less messing about at airports.
If you could only take 3 things…
Waterproofs (you just never know!), a tin of potato powder (it even works in cold water but isnt very tasty) and a hat (for either the sunburn or hailstones).
1. Myself
2. Camera
3. Credit Card
Sketch book
lucky backpack
Tolkien's Lord of the Rings book
The first three things that come to mind are:
- Camera
- Journal and pen
- ipod
But three little things that I aslways pack simply for usefulness are:
- Snap lock bags (1000s of uses)
- travel washing line
- D-shaped carabiners ( great for clipping things onto your pack)
3 things hmmm...
1) Iphone
2) Camera
3) Flip-Flops
-snip-
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[ Edit: Link to Forum Rules added. Sorry, no promos please. ]
passport, camera, knife 
Afaics you need only two:
- passport
- money (credit card)
But a book would be nice, too.
Camera
Ipod
Plastic Money
Money
Photos from home (for breaking the conversational ice in new places)
Notebooks - lots and lots of notebooks (with a pencil attached if that doesn't count as two items)