Margin before admin menu with Views admin pages Screenshot shows the problem:

This margin appears on all admin pages which use Views on Seven theme and module Administration menu. As example, Drupal Commerce products list. Actually this is because of body class .contextual-links-region. I didn't find any issues about it. Can anybody comment it?  

UPD: Problem disappeared after Drupal update to 7.8.
The admin_menu module adds a margin to the top of the page so it can sit there.  I suspect the toolbar module does the same thing which gives you the double margin.

Looking at your screenshot you're using 3 menu modules, which seems overkill to me.  Disable the toolbar module and you should be right.  The admin and admin_menu modules can happily coexist. You can also add custom items to either or both of these menus.

Personally I'd just go with the admin module.