I've always considered/wanted to do this, but the bother of having to actually type in my credentials every time and changing my habits has put me off. IIRC, Chrome won't remember my logins/passwords in incognito mode, correct?
I logged in once in regular mode, then I logged out, enough for Chrome to remember the credentials. When I go to Facebook in incognito I get the login page with credentials filled in, I have to click the login button but that's it.