Currently I am working on a brand identity. I have to decide which color to use but I can't understand how the systems work. I read previous posts here and also searched the internet but still I have questions. 

So I have an RGB color that I like and a CMYK that is vary dull and not similar at all. Should I:

1. Find a Pantone color and set this as my color, and believe that RGB and CMYK will appear the same.
2. Keep the RGB I like and find a CMYK and a Pantone I like and set these to colors (it doesn't matter that they are not listed as analogous if the eyes see them as analogous).
3. Choose a Pantone, then an RGB and CMYK depending how the eye sees it and not depending on the numbers.
4. Keep the RGB and change it into CMYK no matter how it looks.

In short: what are the steps for choosing a color (company uses both printed and digital material)?