I have a power outlet tied into one of my lightswitches. I currently have a lamp plugged into it, but was thinking about plugging my monitors into it as well so that I could easily turn them off when I leave (the switch is close to the door). Would this be harmful to my monitors (repeatedly cutting power/restoring power)?
Not especially - Most PC's/monitors have a sleep/standby mode which does "largely" a similar thing (although not necessarily as effectively because they still need to check for a power signal from the PC to turn back on).
Only partially relevant - In days gone by, monitors used to get their power directly from the power supply of the PC, so that when the PC was "hard" shut off, the monitor followed, and VV. This is only partially relevant because such basic technology was associated with the old CRT monitors.