what is considered "best" choice for video editing
there is only one setting for Final Cut; Generic RGB
This is an apple stipulation, its how Final Cut must be set up, choosing any other profile will cause problems with any out put files you create.
Do top editors calibrate their monitors for video
ICC colour management is designed and can only be used for still image files eg. so while you can calibrate a computer monitor it can only be used with still image files; TIFF CRW JPEG PSD. ICC profiles are not recognised by Final Cut Pro or QuickTime.
The colour management system used in video involves using video scopes, an accurate PAL or NTSC colour monitor and tools like the 3 way colour corrector.