Always forgetting how to do accents on characters, or where the euro sign (€) is? Use the on-screen keyboard and see where the special characters are while holdin down the option key, or the shift-option combination. Read the small tutorial on HackAddict.net on How to Get an Onscreen Keyboard in OSX.
Orange highlighted characters are the combinations. So do an Option-E, let go, and then an “o” to get “ó”. Have fun finding all the combo’s. Using the keyboard viewer is faster than the character palette, and in addition learns you the key combinations for often used characters.
When selecting a keyboard for your new mac, you can decide which keyboard you (want to) have using this article by Apple:
http://docs.info.apple.com/article.html?artnum=304933