This thread will need to exist a long time for downloads to be dominant!
Yup, BR will likley be worth a fair bit. I personally think that how aggressively the industry (i.e. Sony, Samsung, Warners, etc) will push a move away from DVD is being seriously underestimated.
It would be easy to start making BR more attractive while touting backwards compatibility and upscaling of existing DVDs - I think we'll see BR exlusive extras, etc. before too long.
I think many seem to think the industry will now wait and see if people prefer DVD or BR: that's not going to happen, a move will be encouraged nay pushed and DVD will be retired in favour of BR.
Downloads are attractive to me personally but are a long way of replacing physical media IMO so BR will likely have plenty of time to make hay.
As for bigger formats coming - maybe for storage but I doubt movie industry will be interested for a long time now and no matter how big a disk format some small company comes up with it ain't going anywhere without content holders and they are very unlikely to consider supporting anything other than BR for a long time.
All of the above is only IMHO of course...
Try to be reasonable... its easier than you think...