ok, this is gonna be a long one. Flat panels are "by nature" digital devices, hence if you get one with a DVi port it probably will improve picture quality as well as pixel jitter- you just need to know that pixel jitter is bad. In addition, there are things called defective pixels in which 1 or more pixels don't work. Nowadays, that can be avoided with quality models. As for brightness, LCD's really don't have a problem with it- so don't worry about it. As for contrast ratios, anything 300:1 is good- your screen won't seem washed out; although 350:1 is better. There is also a thing called response time which is how long it takes for the crystals to respond. Typically, most LCd's now have response times of 30-40 ms, but that is going down. Of course, if you use an LCD at 0ºC, the response time is seriously made higher. Bad response time makes the image look fuzzy, as well as having a shadow, and response times of 80ms may even make you dizzy. Try to get something with a refresh rate of 75Hz, not the old 60Hz- although it doesn't really matter. If ya want a good LCD, the new one from Sharp are nice, as is the L371 from Eizo.
If you have any more questions, ask me.