LCDs made the jump up to 52"+ screen sizes this year. For quite a while the largest LCDs were 46". If you wanted a larger screen you had to choose either DLP or Plasma.

If lighting is at all an issue I've read that plasma screens are better.

LCD screens provide the best picture quality and if you plan on gaming, they generally are affected much less by burn-in.

The biggest difference between a high quality LCD tv and an LCD computer monitor seems to be resolution and price. Very large computer LCDs in the 28" - 32" range can cost significantly more than a comparable LCD tv. The higher price usually translates into much much better functionality and flexibility of inputs and options, and as much as double the screen resolution, but not always. Some of the newest LCD tvs from high-end manufacturers are closing the gap between tvs and computer monitors.

Just remember that if you buy a large sized computer monitor with some crazy high resolution capability, you'll need to make sure your graphics card(s) can run it.

Aspect ratio: 16x9 or wide-screen, most all are
Contrast 1000:1 or better, it really depends on your lighting
Speed: 8ms response time or better. 5-6ms for games.