TV video signals will appear blurry compared to the sharp image quality from a high-resolution PC monitor.
Graphic cards are designed to output at resolutions of 640x480 or higher. When the TV encoder converts this to an NTSC or PAL TV format, it must reduce the video signal quality to adhere to TV format specifications. While PC monitors generally have a dot pitch of about .24mm (the distance between two phosphor dots), the dot pitch for TVs is at least twice that distance. This results in blurry text on your TV. PC monitors are non-interlaced, meaning that when the screen is scanned, every horizontal line is redrawn. TVs, on the other hand, are interlaced and redraw every other line. This leads to visible flickering on your TV.
For these reasons, TV's are best used to display photos, videos and video games. For text, web pages, and other office applications, a proper computer monitor is recommended.
To improve the image quality on your Standard Definition TV, use the higher quality S-video or component cable to connect your graphics card to your TV. Lowering your resolution will also help improve image quality. Since TVs are analog, the longer the video cable, the more the quality of the signal will degrade. Do not use signal cables longer than 12 feet / 3.6 meters.