Not to mention that if you're still running on component cables, the image quality is still a bit less than VGA, even at the native resolution. And don't even get me started on HDTV lag if you have a LCD. Most games don't have an issue with it, but stuff like DDR and to a lesser extent Guitar Hero is absolute HELL to sync up to what feels right. Then there's the whole 6 bit panel crap if you have an LCD.
Now Ian, on CRTs if I'm not mistaken, those pixels are actually off. At least it seems to be that way since otherwise they would've burned in long time ago. With CRTs, if the resolution is supported, they actually beam the resolutions onto the screen straight on since pixels on a CRT aren't like those of LCD where every pixel on the panel IS a pixel it uses. On an LCD, anything lower than it's native either does one of two things, shrink the image to match the resolution pixel for pixel, or attempt to fill the screen through interpolation and guessing just how it should display the pixels on screen.