We've known since last August that Windows 8 would include a much-improved file copying system, with better ways to track copy jobs and deal with conflicts. A recent tweak to Windows 8 also means you can automatically choose to skip obvious duplicates when copying files from one location to another.
On its Building Windows 8 blog, Microsoft notes that the latest beta for Windows 8 now includes a checkbox which lets you skip any file copying involving files with the same name, date and size after the first conflict is detected. The option is disabled by default, but will remain enabled once you've chosen it. Definitely a welcome improvement.
Acting on file management feedback [Building Windows 8]