Another way to protect your account is to spend $6.50 USD on a
Authenticator. This will add a random secondary password to your WoW account. (In game and at battle.net). While it is not 100% guaranteed to protect from a hack it is virtually impossible for someone to get into your account with one. One would need to be watching you with a keylogger an IMMEDIATELY access you WoW account and change your password before the random secondary password changes and since most keyloggers do not get your info immediately getting hacked with an authenticator is pretty much never gonna happen.
The authenticator password is in sync with the Blizzard server and is unique to you. The password changes every 20 or so seconds. When you add one to your account the WoW login screen adds a third line to enter the authenticator password.