If you think your HDTV's contrast ratio of 10,000:1 is impressive, you ain't seen nothing yet. The Carl Zeiss powerdomeVELVET Planetarium Projector has a whopping 2,500,000:1 contrast ratio. Yes, that's insanely high.
Sure, it's a projector designed for planetariums, not living rooms, but it's still pretty impressive. It utilizes Texas Instruments BrilliantColor DLP technology to get essentially a perfect black backdrop, which is pretty important in planetariums. It's due out next year, and no price has been announced, but it'll probably cost more than your house. Just be happy with your current HDTV, OK?