For professional communications, a signature with full credentials, contact info, etc, might make sense, but for personal emails sigs are completely unnecessary. If you want to add a "personal touch" to your email then write your darn letter in a way that displays your personality!
Putting some inane quote or some retarded link to some useless website at the bottom of your email does not make you any more unique than the seven zillion other knuckleheads who are doing the exact same thing as you.