Well, if your monitor resolutions aren't the same, the sizing will not be right unless you change the resolutions to have equivalent DPIs...however that's going to decrease the whole screen's picture quality if you have a screen on a resolution other than its native resolution.
As far as color and brightness and contrast, etc, that's going to just take a lot of tweaking when you have different brand and/or type monitors. You're just going to have to play around with them. What I would probably do it calibrate my primary monitor, generally the highest quality one, then start messing with the next ones to get them as close to the main monitor's setting as I could.
If you want the most streamlines experience with the best overall quality, the best option is to sell two of the monitors and buy two monitors that are the same model as the main one. When all the monitors are the same model, meaning the same size, screen type, and quality, then resolutions and DPI matches up perfectly, and the quality of the screens is comparable enough to have a calibration on all three create a unified result as far as color, contrast, brightness, etc go.
Edited by MooCwzRck - 6/16/11 at 1:49am