Ok... looks like I've found the solution to the HDMI overscan problem with the G45/G43 Drivers after about 8 hours of digging around on other sites... kinda kicking myself because it was staring me right in the face, I just didn't move the slider over far enough when I tried it the first time.
On the Intel Graphics Properties Dialog Box, display settings tab, click on "Aspect Ratio Options." Adjust the sliders until things "snap" right into place. Don't try to correlate the slider to the amount of overscan on your screen (that was the mistake I was making); it seems that 60-65% for both settings is a typical setting with a HDTV.
It'd be nice of the software could "sense" this automatically, but, hey, at least it's adjustable manually.