When logged in to the Windows Store with the exact same info as logged into the Dev Centre the store seems to be broken.
The login seems fine with Dev Centre - all bits appear to work
With the Windows Store:
If you click the 'Xbox Live games' button as per: 
We get the following error :
If we choose any categories we get ' No results found: 
And searching for apps by name does not work.
If logged out it all works as expected.....