The Nook and Kindle Fire have smaller screens than a 15" TV. A TV with a built in DVD player, if one breaks then you have to replace the entire thing.
Check out Amazon for info on Kindle Fire. I've seen it (DD has one) and the picture quality is good. If you have wireless internet at your home, you can get internet and some TV on it - depends on your cable company and package. Also can get free or cheap tv, like HULU. Do some online research before you decide. And enjoy what you do choose!