Thanks man! When I found these 2 x 16 line LCDs with their I2C serial interface adapter boards on a popular "mostly china" web site on the cheap, and saw there was so much ground already covered on the Arduino forum about these boards, I thought "this is going to be easy". Unfortunately, that wasn't the case, even after downloading this as well as a newer HD44780 library. Part of the problem I'm sure is my own failure to understand, but I think its also fair to say that a lot of details that are probably second nature to those who have built libraries to handle multiple devices, are somewhat a mystery to newcomers. In this case, I downloaded the New LcdLibrary and set it up as instructed in its documentation, but was sad to find even the simple I2C Hello World example did little more than turn the backlight off, and even that wasn't until I read THIS article which explained how to find the proper I2C address.
Anyway, once I had all the pins defined properly as per the example offered here, everything worked, and I was on my way to more complex examples.
It an old post, but it certainly came in handy for me, so thanks again.