I’ve done a few BD vs DVD comparison shots for Close Encounters of the Third Kind now. Have a look. That, with Almost Famous, makes two comparisons unmediated by having to take photos from a screen. So far, the DVD looks dreadful by comparison.
It could have looked worse. For these comparisons I have been using Media Player Classic, an open source product suggested by Simon, to grab the Blu-ray shots. It’s a bit hit or miss, at least on my computer, but the end pictures are rather nice. I also tried to use it for DVDs, but unfortunately in grabbing the shots it seemed to rely on the progressive/interlace flag recorded in the video stream, and performed some deinterlacing of its own which reduced picture resolution. So I have been using Cyberlink PowerDVD Ultra 8 for the DVDs.