It's great to buy TVs or anything else with greater and greater capabilities. That means you're that much more future proof. And in a few years, x.v.Color and Deep Color might be all the rage.
Other than perhaps a few camcorders, there aren't any broadcast or consumer HD sources that support x.v.Color or Deep Color. For your new TV to take advantage of either one, the source must either be captured using x.v.Color or Deep Color, or transferred from film using x.v.Color or Deep Color.
Everything coming out on Blu-ray Disc and HD DVD, does not conform. Nor does any HD broadcast currently. In both cases increased bit depths would also take up a significantly larger amount of disc capacity. Talking with industry reps, it's believed that these new "standards" will first come to our TVs through gaming, if that's your thing.