Last Summer I was experimenting with using a Windows 7 machine as a home theater PC and ran into an issue I thought was obsolete - overscan.
Overscan goes back to the days of CRT TVs where the edges of the image are cropped off by the bezel of the TV so the picture completely fills the part of the picture tube that you see. I thought that it was an obsolete concept with the advent of HDTVs. So imagine my surprise when I hooked up the computer to my Samsung 46" LCD HDTV and found the icons on the left edge of the screen were clipped off as well as the task bar. It turns out that even though the physical resolution of the LCD panel is 1280x1080 the TV was stretching the pixels to clip off some to accomplish the overscan.