It might not matter for low impact stuff like forum memberships, but major emails, ebay, paypal and banking passwords have to be separate, random alphanumeric with characters and long enough.
Otherwise it becomes too easy.
Another way to defeat keylogging is not to enter the password in one go. IE if your password is 12345678, then enter 123, type something, enter 678, type more, click in the middle and enter 456.
It would make it a huge PITA to put back together if you have a keylogger.
This is an excellent idea.