Mark,
There are so many ways to go on this subject:
1. IP Cams, 2. Webcams, 3. Security type SD Cams... I would reply by saying what is your goal? Do you simply need visual connection with average quality? If so, IP and WebCam type products would work. If you are going to put up large format LCD monitors, the resolution of the cameras will come into play... Some of these cams are 2MP, but some are much less. A 1MP camera should display ok on an HD display, but remember there will be issues of frame rate as well.
Now... let me say I am NOT an expert on video... We have a few customers who have spent a lot of time and money putting in video communication systems for remote recording rooms to control rooms. I've seen it done so many ways, that as with most things, it comes down to 'you get what you pay for'.. Having said that, I suggest you evaluate your needs (and wants) for the system and shop accordingly (by price).
LCD displays will continue to get cheaper and cheaper until the next resolution advancement (2K/4K HD) becomes available to the consumer.. don't know how long that will be. (let's see what shows up at NAB this year). Watch tigerdirect.com for some absolutely stupid pricing on HD LCD TV's... that's where I would buy mine!!
Let us know what you come up with... as I'm sure there are others who are wondering about similar subject... thanks!!
fm