My KD-34XBR970 shipped from the factory with a fair bit of overscan… about 10% of the picture on the left and right is cut off, and about 5% on the top and bottom. Sony customer care said they would be more than happy to fix it, but that requires moving a 200lb TV to a local TV repair shop…
You can address the overscan yourself by putting the TV into service mode and adjusting the display parameters. Obviously you can really screw up your TV good doing this, so beware..
To enter service mode turn the TV off then press DISPLAY, 5, VOLUME+, POWER. The current parameter group appears in the top-left and the current parameter appears below it. You can change parameters with 1 and 4, parameter groups with 2 and 5, and the parameter setting with 3 and 6. To save a parameter setting hit MUTING, then ENTER. You have to save each parameter setting individually. I would recommend you write down the default for your TV before you change anything! Here are some parameters I found useful for adjusting overscan:
MID1/DHPH – horizontal position
MID1/DVPH – vertical position
MID1/MDHS – horizontal scale
MID1/MDVS – vertical scale