I always watch television with captions on. I am not hearing-impaired, but often I am doing something else, or accidentally miss a line or two.
Caption quality is horrible. Watching the news with closed captions on is an unique experience. Often you read things that have nothing to do with the subject at hand. Most of the time, half of the content in the news does not even make it to the captions.
However, cursing is often left in. This makes watching stand-up comedy on comedy central more enjoyable, because you can actually understand the jokes, rather than hearing a "beep" for 10 seconds.
I pity deaf people who watch television, but not nearly as much as I pity the blind, for at least the deaf can read lips.
I guess that doesn't really help while watching The Simpsons though...