At the moment, for standalone movie playing media, the DVD takes the UMD out no hands, but there are many things that could be taken into consideration for future generations of these media.
For example, the UMD's 1.8 GB capacity is based on their current single layer media, but just adding an extra layer doubles at 3.6, which could mean higher quality movies. Not only that, but all video UMDs are sized for a current PSP screen, as they are the only devices to utilize them at the moment. If that stands the same until the next generation of the system, we may be seeing movies sized for a larger screen, perhaps 1.5x the size of the screen now. If not, then we'll see movies optimized for larger screens, probably for televisions or possibly other portable devices. Another small point and possibility for future versions of the UMD is the support for music on the PSP, and possibly other products.
On the DVD side, you need to look at both upcoming formats, HD-DVD and Blu-Ray, as either could be considered the successor to the DVD. With both, we'll be seeing high definition movies, or possibly multiple movies on a single disc. Considering that both will have more support than the UMD in terms of marketing and the supporting products they'll release, consumers will obviously see these as the media of choice for burning music, file storage, etc.
Bottom line- if a UMD burner isn't out by the end of the year, they'll won't put a dent in the DVD's share of video media's market, nor be seen as the media of choice for data storage for atleast two or three more generations of the media. If so, the UMD's successor could put a small dent in, and may grow slowly in the future- if that's what Sony even wants.
