Well not all. I guess Sony pictures will only release DVDs on Blueray for as long as possible to juice their proprietary shit, but most companies will go with the dual format rather than having to try and sell two separate copies.
As of right now the smart money is going with Bluray. Technologically speaking it's a slightly better format, but I think the real problem was when Microsoft tried to shove HDDVD down peoples throats (i.e. Hollywood).
My personal feeling is that HDDVD will die much like Betamax did, for similar reasons. Not because the competition is particularly better, but because of marketing mistakes and bullheadedness.
Kuhlka is right that there will be dual format players soon, but they will be a short term thing until one of the formats dies because nobody is releasing titles on them.