I've been checking out videos all week too and I'm a bit baffled myself.
I think Metro will be the way for social apps, browsing and certain smallish Applets (like phone apps), but I doubt that - given the information we've gotten so far - that you'd want to build any heavy duty applications with this interface. It's meant as a consumer front end that's geared mostly to - consuming data and visualizing it. It's not going to be that useful for data entry or displaying LOTS of data.
Looking at what I see I think this is one of those V1 releases that will have to prove its worth. I'm sure there will be lots of Metro apps - most of them garbage - just like 90% of apps in various app stores (including Apple's) are garbage. Finding good use cases for the Metro API is going to be the key.
The fact that there's no local data access with all data being served from services is also going to seriously challenge what kind of applications you can build. It'll be interesting to see if Microsoft will have a Metro version of Office? I doubt it unless its a very stripped down version that integrates with Office online.
Metro seems like a great idea for readers, and interactive, connected apps and to me at least fits the tablet and phone market. But building data heavy applications will still land on the desktop I think.
+++ Rick ---
>Did I miss the thread on Windows 8 and Metro? I figured people would be talking up a storm about it here. In any case, here are my thoughts and some things I've learned:
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http://weblogs.foxite.com/joel_leach/archive/2011/09/19/14650.aspx