What is the purpose of the resistor that sits in front of the LCD display exactly? Is it to lower the voltage so that the display is not too bright ?

Are you referring to the one that is on pin 3 of the LCD connector? (at least I THINK it's pin 3)

Yes the only one that's connected to the LCD connector.

That one is the contrast control for the LCD. My setup goes a little further and is adjustable with a small trim pot across the +5V/Gnd lines with the wiper connected to pit 3. It gives a little better control over the display's appearance but is not necessary, The 1K resistor to Gnd is usually sufficient for the display to operate. I have a photo in another thread that shows the trim pot in the circuit.Here is the linkLook for the Dec 30 post for the pic.