The actual resolution of the shows at 100% is 1440x800. It's not a standard video size by any means but that's what they are. So that's the 'ideal' res to have them fill your screen and not get cropped/clipped anywhere.
With LCD monitors, the sharpest image is always at the montitors native resolution. Any other will look softer as the montor has to scale the input. Depending on how good a monitor you have it can affect quality quite a bit.
So it's a trade off. I know alot of people don't see it, and bigger is always better for them. I always run at native res, 1920x1200 in my case, with the girls at 100% as that's as good as the girls will ever look.