I don't believe either will become a standard. A LOT of companies are developing players that will play both BluRay AND HD-DVD...
Both have their advantages and disadvantages, however a decent Blu-ray player is ~$1,000 where an HD-DVD Player can be bought for less than $200 now! Blu-Ray at the time can support a better picture, but only true enthusiests will spend that much money on a player!
98% of the market is people who just want to watch HD for a reasonable price, and most of those people will not even notice the difference in quality!
If I had to guess right now, I'd say HD-DVD will be the most common for now. If and when Blu-Ray comes down in price, it may become the standard however most companies are making their players compatible with both.
It's really too early in the game to tell, especially because no one knows what the standard is going to be and they're afraid to purchase something that they won't be able to use in a few months!!
This reminds me of when Mini-discs were released - it's a great technology! However they were very expensive and the majority of the market ended up buying MP3 players because of price. Unless they were a true enthusiest they weren't too concerned with sound quality, only price...