Provided that you have chosen a safe password as described in section 1, the local risk is simply that you will be observed typing it in. The fact that your password is masked on screen is irrelevant. If someone in your work environment is determined to find your password, they can arrange to be in a position from which they can observe (or even film) what you type.
The best way round these risks is to use a password manager like WebM8. Once Webm8 is activated, your passwords are entered by a mouse click rather than by being typed. Apart from avoiding the risk of being observed, it also avoids the embarrassment of asking a colleague to turn away while you enter a password, which implies mistrust!