Comment 11 for bug 619477

Although your mockups are nice, I'd like to argue the points you make:

1) Unity is by itself a new paradigm, so button location will be one of a dozen of new things users will have to get used to. Doesn't make a big difference.
2) Dialog windows should have their own buttons and it makes sense as they are child windows with local context. Makes it even easier to distinguish them from application windows.
3) Since Unity is designed for netbooks with small screen sizes users will rarely have unmaximized windows anyway.
4) The gap between Ubuntu logo and main menu has exactly enough space to put window buttons there, anything else will look awkward there however hard you try.

With buttons by the main menu the interface becomes more consistent and simple. It will be easier to train ones reflexes if all the major application wide controls are in the same place all the time.

This is also perhaps the easiest solution to implement as all the pieces are already in place.
Now that the release date is approaching fast this argument suddenly becomes important enough :)