One thing you sometimes need to be careful about -- the DPI settings for the display. Rule of thumb that I go by -- selecting "large font" (120dpi) is equivalent to reducing display to one size smaller ( 1280x1024 --> 1024x768, 1024x768 --> 800x600, 800x600 --> 640x480 ). Larger DPI settings would reduce the effective display size further. Once ran into a situation where an older software designed for 640x480 ended up with stuff going off screen on a 1440x900 display because of a 200dpi setting. Of course, due to the various things that happen with different dpi settings -- yet another reason to not force a display resolution change.
One other bit I should also mention -- using a display resolution that doesn't match the physical resolution of the display is much more of a problem on LCDs than it was on CRTs. If you select a lower video resolution than the display, you usually get one of two things:
* only a portion of the display is used -- that is, you get something that looks like a "window" in the middle of the display with everything else blank.
* A blurry display.