I have a 24 inch LCD monitor (19:10).
For instance, when playing the game "Skyrim" I notice _very_ little difference between 1920 x1200 and 1440 X 900 resolutions. With the latter resolution, I am able to heighten the anti-aliasing and anisotropic filtering, and the frames-per-second performance is still marginally better.
I am unsure whether I should play with my monitor's native resolution (1920 x 1200) and play at a lower detail setting, or lower the resolution to 1440 X 900 (which does not seem to be much of a difference to me) and play at a higher detail setting (AA X 8, higher texture filtering, etc.).