LCD TV's will have a maximum resolution of 720p or 1080p depending on the set you have, typically when you reach sizes of 32" or larger a computer monitor will give you significantly higher resolution than an LCD TV of the same size.
LCD TV's typically have HDMI inputs and D-SUB analogue monitor input, neither provide the same quality as a DVI input from a PC however there would be little difference to the untrained eye but if you do any colour-sensitive work it would make a difference.
PC monitors typically don't have multimedia interfaces however like composite or component inputs so it won't take feeds from a digibox or satellite receiver etc. Monitor/TV hybrids mentioned in a previous post often do however so are a happy medium.
When I hooked my home TV to my laptop (via D-SUB) it identified itself as an LG 50" whereas my model is a 42" version of the same TV, it also didn't detect the dot-pitch correctly resulting in unreadably under-scaled fonts. I have a feeling that TV manufacturers don't always bother adjusting the configuration for different size models like they would for a monitor but it could be just me. However, I have a friend who uses his PC with a 32" TV quite happily, but it's a matter of taste, personally I don't like moving my head to hunt around the screen.
You should also consider your eyes, large screen TVs are designed for remote viewing, if you plan on sitting up close the screen may default to being very bright and need adjusting.
DS Nelson
Performance and Improvement Analyst
Zen Internet Business Support Unit