As we know Windows 7 RC has been released to Connect, TechNet and MSDN subscribers and public release is set to 5th May.
The first testing build of Windows 7 released to public was Windows 7 Beta build 7000. If you are still using that Beta build and want to know what things have been changed or added in RC build, then you should watch a new video which has been released by Microsoft:
This video walks through all new changes and features implemented in Windows 7 RC build.
You can also read following topic which describes some new and interesting features of Windows 7:
Also make sure to read some important information about RC build given at following link: