Firingsquad created a new autumn 2007 video processing roundup in which they compare upsampled DVD, Blu-ray, HD DVD, ATI's Avivo, NVIDIA's PureVideo and the PS3. Here's a small snip about what they've have to say about DVD upsampling:
The next time someone claims that upsampled DVD looks just as good as Blu-ray, you should point them to this article. Sure, you can do a lot of hand waving or argue that if you sit 25 feet away from your 25” TV that DVD and Blu-ray are identical, but for rest of us, high-definition media such as Blu-ray and HD DVD will clearly provide a step-up in terms of performance.
The PlayStation 3 is one of the surprise winners in this round-up. Not only does the PlayStation 3 offer Blu-ray playback support, but its DVD upsampling and detail enhancement with Hollywood movies such as Pirates of the Caribbean is better than even the best HTPC solutions from NVIDIA and AMD. Keep in mind that this test doesn’t consider noise reduction (available on the PS3 for DVDs), unusual cadence detection, or even 480i deinterlacing.