Here’s a screenshot (click for full size):

A summary of the changes so far:

  1. Window, Utilities, and Help menus are now button menus in the top-right corner. They are still menus, and behave as such (as in, they are not some weird custom button control).
  2. The floating tool window now use a more compact, glass-less styling.
  3. The image list has been “pulled up” into the title bar area. This has several advantages. First, if follows the Fitts-Law-friendly convention that Firefox and Chrome have employed whereby the tabs are docked to the top edge of the screen when the window is maximized (the title area is always draggable, for all of us Aero Snap fans). This ensures that the image list does not get “shoved around” when a tool needs more horizontal area (such as the Text tool). And, it ensures more horizontal space for toolbar controls (which will become important later!). 
  4. The zoom and controls have moved to the status bar area, and use a slider instead of a text combo box. It works much like the one in Windows Live Photo Gallery. The units selector has also moved to the status bar.
  5. “Paint.NET” is now “”

Some things probably not apparent in the static screenshot:

  1. The image list supports drag-and-drop reordering. The dragging is live (I don’t employ an “insertion arrow” ala Firefox), and sports the same types of reshuffling animations you see in the Windows 7 task bar. Fade in animations are also used when opening or creating an image.
  2. Speaking of Windows 7, each image shows up in the task bar thumbnail list. If you hover over the Paint.NET icon, you’ll see a list of images instead of just 1 thumbnail for the main window. This can be disabled in Settings, just like in Firefox, at which point you’ll get 1 tab for the main window instead of 1 per image.

These are just some of the cosmetic changes. There are, of course, many other little and not-to-little changes.