What I (whole world) had chance to see in global speech by Steve Ballmer, I would say yes!
I am more skeptic when it comes the question of timing - because - I (even as Windows Mobile/Phone supporter) am using 3rd generation of iPhone (3GS), second one in a row, and I can see that a lot of companies are developing apps for iPhone, but not for WM, or the are developing it after they developed apps for iPhone (last example is Lufthansa and Miles & More).
Why I am skeptic? Because on Windows Marketplace for Mobile I could not find vendors/applications like Skype!
Do you want more to support this? There is iPhone App for MIX10, which btw, starts today on March 15.
What is cool about this? It was written by using C# and MonoTouch from Novell.
What I am happy about - I can name support by partners - HTC, QUALCOMM ... this will actually give life to WP7S platform, I hope soon!
From the technical point of view, I do not like that Windows Mobile Device Center is not working on 64-bit Windows 7 OS!
What I like about WP7S? Finally (after almost 3 years) it supports Silverlight, as well as XNA. I also like the 3-screen model, as well as support for cloud.
It is funny, that first WP7S public presentation on some big MS event will be at MIX10 :-).
I am a little bit worried about rumors that Microsoft will charge for SDK :-(.
Still remains question of OS updates - this is (almost) number 1 request for WM platform, often justified by the "hardware vendor lock".
Opposite to the opinion of majority people, I think that Windows Phone 7 Series (WP7S) can be also good for the Enterprise environment - because today people "share" their work and public workspace and they do not want to carry two mobile devices.
More about Windows Phones: http://www.microsoft.com/Windowsmobile/en-us/default.mspx
Windows Mobile Marketplace: http://marketplace.windowsphone.com/Default.aspxAbout