I don't see this deal as making a big difference.
Warner Brothers has some huge titles that are pretty much HD-DVD exclusive RIGHT NOW, and that's not affecting the sales momentum of Blu-Ray over HD-DVD.
That being said, I am a bit mad at this announcement, as it makes absolutely no sense unless money hats were involved.
Overall, the only real 'loss here' for me personally is Paramount. Transformers was garbage, and while I'd like to have Shrek in HD, it's not a huge deal. If they want to go exclusive to one format over reasons unknown, then I'm not going to support them and give them my money.
I have enough titles to buy in 2007 with the Spiderman Trilogy, Pirates 3, Ratatouille, and Die Hard Trilogy that I don't really care.
It'll be funny when Blu-Ray expands its lead to 3:1 soon, while the Paramount announcement does nothing to significantly boost HD-DVD sales and merely acts as a means to rile up HD-DVD fanboys on the internet more than anything else. Most of the movies I want from Paramount include the Indiana Jones series, which is going to be format neutral.
In the end, I'm still supporting the best format with the most studio support, and this doesn't compel me to run out and grab HD-DVD. I won't be supporting an inferior format simply because one company chose moneyhats.