For the longest time to me, a TV normally in the living room is just that a vanilla TV. A computer monitor's an enhanced TV on steroids even during the color CRT days and is the only way to go when paired with a PC for general work, gaming, photo editing..etc and for anything you want to use close up on a desktop.
But in the last few years, the line is blurring more between these two type of visual displays. Depending on what you want to do, choice of display type requires you look closer a the specs closely before deciding what monitor or TV to buy.
I never used a TV device plugged to a computer for graphic design/editing, photo & video editing, hardcore gaming, watching multimedia...etc. To do all that in my limited size bedroom, I have a 30" Dell IPS monitor ( U3011 ) which offers a maximum resolution of Full HD 2560 x 1600 at 60 Hz. It has a very long standing reputation for being one of the better monitor to own if serious about your work or gaming on a desktop like me. And I have this for 4 years+ and even if I get another one, it would be another PC monitor and not a TV.
My Dell came calibrated and certified by Dell. A good monitor for what I use it for MUST have color space that includes
sRGB and AdobeRGB. To me, these two are the most important color spaces for any creative work. Compulsory. Monitors also have screen refresh rate of 60 MHz for more years though TV has caught up to offering that in the last decades especially when it went flat TV. If there was one very important reason for choosing a PC monitor, it is the color space. Also monitor are better for calibrating the colors if you own a color calibrating device. And you can really make full use of the graphic card in your PC.
Monitors tend to offer higher and true pixel density and not interpolating to simulate higher resolution. True pixel screen of 2560 x 1600 if you load a picture that is also 2560 x 1600, will fill and fit the screen in real pixel as captured by your camera sensor for example. A 100% scale photo that fill your screen tend give you the best view of the photo with no jaggies from interpolation by your screen. Thus, its always better to have a reasonable screen size ( 27" to 30") monitor with a higher pixel count to photo or video edit.
When you load a 16M photo which is about 4928 x 3280, its always easier to work or view higher resolution photo on as high a resolution screen as you can afford short of surpassing the photo's pixel count. heh Still rare but there are 4K (or higher like 5 to 8K) TVs and Monitors in the market which might fit your need if higher pixel count is vital to you. Apple has one that is 5K for good reason. If you look at application like Photoshop, Adobe Premier or Lightroom, imagine being able to open a photo in full real pixel size in 100% scale and still have room to fit all the menu of tools around the photo. This is especially good for video editing.
For NOW much of what i said here does not quite cover 4K monitors though you can buy one for the advantage of the higher resolution. But for this discussion I just want to say why I prefer a PC monitor over a TV for other reasons apart from resolution. If you want to know more then, maybe you can ask me on a reply heh.
At this time, majority of flat screen TVs are mainly 1280 x 720 for older cheaper models and 1920 x 1080 for the more higher price models. And for some TV they might even use interpolating resolution meaning it is not true pixel count so be careful to double check and not be misled. These days you can buy a 1920 x 1080 resolution TV in screen size of 24" to 46" or larger. Meaning, that tiny single pixel square will be larger on a 46" then on a 24" screen. So imagine you buy a big screen and you sit 2 feet from the screen editing. You see each pixel clearly. It can irritate some people and maybe you are fine with it.
Also, when it come to screen size, I feel 30" is big and about as large as i go. I rather buy another monitor and do a 2 monitor set up then an even larger one to work on. Its just getting a little large to edit as you start to roll your eyes to look at the extreme corners of the larger screen from 2 feet away or you turn your head about often heh. When you watch a movie, you can sit back a little to watch but when you are editing, you tend to get up close naturally over time as you focus on certain touching up..Thus.. I rather have another screen or two on the side where maybe I have a movie playing on one as I am editing on another and another where I have my tweeter/CS and Facebook all open up on auto update LOL.
If you are going to use a TV plugged to your PC, never go lower then HDMI.Because of the higher resolution and other graphic data, HDMI push out the signal faster and more efficiently then RCA or VGA.
For more details
click this link to know more about various cable connect to a TV or Monitor
If you game on a PC and not a game console, it is better you use a monitor then a TV. A lot of the enhancement of a good PC game will look better on a monitor, will render better without ghosting, texture rendering looks better..etc.
I am sure there was another important reason why I prefer always to choose a monitor.. but some how.. it just slip my brain as I type heh and i can't get it back. Will let you know if it pops back in
