When you take into account that standard analog broadcasts are only 330 lines of resolution and you are putting that onto a 47 inch monitor, you be the judge as to how good it will look. Digital cable looks halfway decent on these sets, increasing resolution as high at 480 lines of resolution, or close to DVD quality. Keep in mind though, that some stations are still broadcasting only analog. Lucky for us, the initiative set forth by the FCC states that analog broadcasts will cease completely by 2007 I believe is the year. Could be 2006, I don't recall. People with analog only sets will have to purchase digital to analog convertors to even watch TV.
Also, by 2006 most stations will be broadcasting mostly HD content. Of course some of your lower budget stations will probably not come around for a while, most normal programming will be HD. Already, almost every national station's broadcasts between 7-10 pm are all in HD with only a couple exceptions.
To answer the ultimate question from this thread, you need to sit at least 8 feet back (screen to eyes) for this TV (or any similarly sized 47-inch HDTV) to look half way decent. As stated, analog broadcast artifacts will only be exemplified more easily on a larger television.
Chad