yes the DTV and the HDTV are different and the first thing you notice is the quality of the picture, a tv with a HDTV tuner will allow you to watch both
DTV and HDTV so as we do you can flick between the 2, it is however a waste of time to get a HDTV box if you have a standard TV as the HDTV requires a higher resoloution tv, the big con in oz was a lot of tv's that are suppose to be HDTV ready are infact not as they are not high res tv's but smart arse marketing people stated that as you can plud a HDTV set top box into the they are ready, just like a vista capable pc will run vista