Well, for consumers sake, there should have been only one format. Sony, broke away and decided to go another route, with them they took others to follow. Blu-Ray is different (big thing is more space) however, with that, I feel most over look the fact that Blu-Ray would have a higher failure rate (one little scratch would damage more data, compared to HD-DVD, am i not right here?). So it is like a car that holds 20 gallons and one that holds 10 gallons, of course, the 20 gallon capacity is better, but if the 20 gallon tank is in a vehicle that has a V8, it won't travel any further than the 10 gallon car that has a four banger... Another way of looking at it, if 20 gallon tank had twice as many holes as 10 gallon, it would not be any better on reliability.
Everyone needs to look at the big picture, and realize, neither is really that great compared to the other, both are mediocre at best. If any of the two win, then it will be because of marketing, and not absolute ability of the format. Will one of them replace DVD's? Maybe. When? Who knows...