On my PC, I have 2 19" CRTs. Same brand, same model. Works great. On my Mac, I have a 22" LCD and 15.2" LCD, both widescreen. Works great as well. Personally, I like LCDs better, because there is much less strain on my eyes. I've been using dual monitors for so long that I don't notice whether or not they're the same sizes. What's more important is image quality. As long as you have nice monitors, it doesn't matter what size they are.