Shoppinglist, what will i take with me?

Knowing myself i usually pack too much (better save than sorry). Therefore i didn't want to buy a backpack too big. I ended up choosing a Haglöfs OXO 550Q meaning 55 litres contents.
There are some things i really want to take with me, first of all my canon 350D with 2 lenses, a tripod for my camera, my laptop and my trumpet (i've been playing the trumpet since i'm 8-9 years old).
Fortunately i found a small backpack from Lowepro, where i can stash both my laptop and SLR camera (including lenses) in special compartments. this means i don't have to take my a seperate camerabag with.

Who, where, when, why????

Me, Hans 28y from Belgium.
Australia (OZ, Down Under)
No fixed date yet, but at the latest starting halfway the month March 2009.
When i travelled OZ in 2005 i immediately fell in love with the country and it's inhabitants.
turning 29 in 2009 i figured, now is the time if i ever want to go for 1 year (or more)