I agree with Ted. Changing your password regularly is a good idea. Also, don't use the same password for more than one site.
Generally, I use 20 character passwords (or more) for sites that deal with my money. It's a good idea to use upper case, lower case and numbers.
You can copy and paste the password from notepad so you don't have to hassle with typing all those characters.
This is what I use:
http://www.pctools.com/guides/password/