Hi chksix, just went for a flight in the C172 today, and took a plum-bob.
It showed that the lower tip of the prop is a good 4 inches in advance of the top blade, making an angle of about +4 degrees wrt the vertical with the nose-wheel suspension at its usual 3 inch extension.
I could not detect any significant side thrust, as the canopy is not too solid, and my measuring string was a bit elasticy.