First I doubt that the last gun in the format 'question' has been fired yet. Currently, more studios are signing up for BluRay, but the players are still SO much less expensive in HD, and that will surely cause a swing eventually in disk sales. Even though I intend to got format neutral as soon as I can afford a BD player as well, currently my purchases are VERY strongly slanted towards red. And I find it hard to believe that others are not doing the same. Remember, it was player cost that killed Beta, and guess who was responsible for that?
But even if no one ever cuts another HD disk again, your current collection and player will still be good for a long time to come. Don't replace yet again until blu prices come way down, like standard DVD prices did over the years.