I just bought a 57 inch DLP, XBOX 360 Pro (sku with hdmi out), Blue ray player.. Comcast also gave me HD Cable box, so I needed 3 HDMI Cables. I bought them from some website, six bucks each. One of the cords puts a slightly scratchy picture up no matter which device I use it with.. the vendor I used is happily replacing it.
Anyways, the cheap ones are just as good as the $70 according to many tech review sites.