Not a whole lot has changed since the beta - Windows 7 RC1 is primarily about bug fixes, speed boosts and other refinements. However, there are a few new features in Windows 7 RC1, most notably.
Another cool part of Windows 7 RC is wallpapers, cool wallpapers which you will love to have on your desktop.
Windows 7 RC1 will reflect the same code that will be found in Windows 7 Ultimate Edition, the desktop environment with the most bells and whistles.