There's a comparison online that may be of interest. I found it scrolling through old AVSForum threads. It compares the HDTV Broadcast and the HD-DVD, which should be nearly identical to the BD. While the photos are compressed to hell (lots of artifacting), they clearly show a difference in color and contrast. The HDTV seems generally brighter.
Here are the comparisons:
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img228.imageshack.us/img228/1938/brhdnet1lo6.jpg&sd=http://img148.imageshack.us/img148/8493/brhdm1hv2.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img148.imageshack.us/img148/2458/brhdnet2ve8.jpg&sd=http://img228.imageshack.us/img228/1372/brhdm2cb0.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img230.imageshack.us/img230/6307/brhdnet3ta8.jpg&sd=http://img230.imageshack.us/img230/4166/brhdm3kh5.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img80.imageshack.us/img80/2642/brhdnet4wm0.jpg&sd=http://img115.imageshack.us/img115/7615/brhdm4cd3.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img80.imageshack.us/img80/8742/brhdnet5ey1.jpg&sd=http://img230.imageshack.us/img230/3696/brhdm5vn4.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img80.imageshack.us/img80/1170/brhdnet6qe5.jpg&sd=http://img115.imageshack.us/img115/7177/brhdm6sk4.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img85.imageshack.us/img85/8499/brhdnet7bp2.jpg&sd=http://img91.imageshack.us/img91/9525/brhdm7gw8.jpg
http://horn.hdtvtotal.com/hdtvtotal/scripts/waggle/waggle.php?hd=http://img85.imageshack.us/img85/3528/brhdnet8pp4.jpg&sd=http://img91.imageshack.us/img91/2760/brhdm8pp8.jpg
So, what do people think? More or less 80s-esque?