Higher Resolutions, But Not High Enough
Most HDTVs have a resolution of 1280x720 (720p), 1920x1080 (1080i/p) or 1366x768, which is also generally designated as being 720p. These resolutions are significantly similar to what can be found on computer monitors, although not exactly the same, as widescreen HDTVs use a 16:9 aspect ratio, while most monitors use 16:10. The higher resolutions of HDTVs allow them to display a much finer picture than possible on standard tube TVs. At first glance, then, you would think that modern HDTVs, with resolutions so similar to computer monitors, would be easy to use with a computer.
Unfortunately, that isn't always the case. Size matters, and the larger the television set in compared to the resolution, the less fine the image will become. When watching Jackie Chan beat down thugs with a trashcan lid, this isn't noticeable. But when viewing small text, like what might be on a website, the limitations become easier to see. Sure, a 42" television offers a resolution of 1920x1080. But the similar monitor resolution - 1920x1200 - is commonly reserved for 24" monitors. 42" is much bigger than 24", but both have the same resolution. That means the pixels are larger.
This means is that when viewing things that require very small pixels, like a text document or a web page, an HDTV tends to flunk out. Even when using large text, anti-aliasing, and other methods to mitigate the problem, it is still unlikely that any HDTV will serve very well as a tool for doing work. Also, although the 42" television may be much larger than the 24" monitor (and much more expensive, as well) you won't be able to do more with it. They have a similar resolution, and it is the resolution, not the physical dimensions of the display, which determine how much you can view at once. In other words, if you're planning to buy an HDTV to, say, use Photoshop or edit web pages, forget about it. You'd be wasting your money.