About the buzzing noise...
Since Boxing Day, I tried 6 units, finally got one with zero dead pixel. Wow, 1 out of 6, poor yield! All 6 had the buzzing noise, some are slightly louder. Unfortunately, the price is now $370 compared to $330.
VGA port has the brightness mapped to the backlight. The Picture/Text/Econo modes change the backlight which generates the buzz. The brightness control behavior is different than other LCD or via PC video.
HDMI port has separate brightness and backlight controls. I connected it to the PS3 on HDMI. The Picture/Text/Econo modes change the backlight which generates the buzz. The brightness control does not generate the buzz.
This inconsistency would explain why some people don't hear it, because there is no buzz from the brightness control on HDMI. I believe the buzz is in all the units if the VGA port is used. Don't know about HDMI via DVI adapter.
I think a new firmware is required, to decouple the brightness and backlight in VGA mode.
I have various ACERS and one NEC and one cheap DELL, don't recall they offer backlight control. The backlight controller uses an inverter and buzz is common.