Special characters in OS X

I have the keyboard layout option icon in my menu bar to enable me to switch between English and Portuguese keyboards (actually I wanted Brazilian Portuguese which although it is actually available has no Portuguese characters).
Nevertheless, there are some interesting additional tools in this menu bar item. First, there's Show Character Palette which brings up a huge range of different characters that can be inserted into a document as you type.
Second there's the Keyboard Viewer that lets you see what characters are actually available on your chosen layout and I'm not just talking about the ones that are printed on the keys but the additional ones you get by pressing the Option and ctrl keys. Even dead-keys are included.
This is very useful as you don't have to trial-and-error till you're blue in the face to find a special character.
I even found out that I can get ALL of the Portuguese characters I need from the normal English layout.