OK. But what white point do you calibrate your monitor?
If you prapare content for printing - it is quite easy. You adjust your monitor's white pont to ambient light.
But what is wite point standard for video editing? Do I have to adjust it to the color light in my room?

Actually tools like Spyder Pro can fine tune your monitor just fine in the ordinary way. But if you are asking for managing preview out of Vegas and not a second card output - then I question what you will finally expect to accomplish. WHAT -You want to understand - how Vegas manipulates video preview and that is best done with preview window being less tweaked and absolutely flat.

videoITguy - thank you for the information.
I have been participating it those long threads concerning Computer RGB <=> Studio RGB conversion. So I understand how to set the preview monitor correctly.

What I do not understand is the white point calibration.
So if I understand you correctly, if I calibrate the preview monitor as an ordinary sRGB (computer RGB) monitor (white point = 6500K), I will get accurate colors.
I'm afraid of a situation that I shift white point to much. Then, when I perform a color grading, I may over correct the image. For example: I have an interview footage. It needs color correction. I do this correction using preview monitor calibrated to white point = 3200 K (warm). In the result the image that looks correct on my monitor will look very bad on monitor calibrated to white point = 6500 K. In the result the skin tones of the interviewed person will look very bluish, as he would have died two hours ago.

I simply do not know what white pont should be set for the industrial standards like rec. 601 (DVD) or rec 709 (HD).

You use the monitor's native white point.
This has no connection to white balance, a camera adjustment that is not static.
Apples and oranges; you're doing it again.