I really wanna buy a new big screen TV, but it bothers me that the tech is moving forward so fast, so the YV will feel obsolete in a few years, plus the prices go down so fast.

Two things to add.

First, even though those advanced modern coal plants pollute much less, many new coal plants are still built with old 'dirty' designs, because of the cheaper startup costs. Even if every new coal plant built from now on is a 'clean' gasifier design, the existing dirty plants will probably keep operating and delivering power for decades. Whether you get clean coal electricity or dirty coal electricity will be an accident of geography.

Second, energy prices have been rising and are going to keep rising for the forseeable future, so if you're expecting your TV to last you for the next decade or more (I am), you can expect those annual savings to keep on rising. Over the lifetime of the TV, you might even save enough to pay for your next TV.