I am a paranoid when it comes to auto-filling passwords, especially when it comes to websites where our clients' data reside.  I don't even install the toolbar for the manager in my browsers.  I do, however, use a password manager (Norton Identify Safe) from which I retrieve my passwords when logging into various websites and would clear the cache for clipboard immediately.

For Intuit though, I have my password pretty much memorized and use different iterations of that when it comes time for update, so that I don't have to remember another big password.