Things you should bring
Warm clothes (it can be quite cold)
Flashlight (in case of power cuts)
All the money you need (you can also withdraw money from you bank account at Victoria Hotel)
Swim shorts (if you're going to Cat Cat waterfalls)
Extra space in your bag (there's a lot you might want to buy)
Passport (needed to check into some hotels)
Walking boots
Camera (duh!!)
Of course you might want to bring stuff like portable CD players and such but this list is based on things you really need up there.