I was providing at least 3V through my body. Is that right?
Yes that is correct. You only need a very tiny amount of current through your body.
if using a 100 ohm resistor between a 5V power and a pin was a safe way of keeping the arduino safe.
For a discussion of protection of you input pins see:-
http://www.thebox.myzen.co.uk/Tutorial/Protection.html
but it is not needed for normal playing about with the Arduino.