I tend to choose color by these rules and judge by how it looks on me:
1. Basic or must have colors (Natural) - As in Black, Gold or MF, White or beige.
2. Fun colors ( Color that pops and makes me happy) - Fuschia, Red, Blue, Yellow, Potiron.. list can be expend.
I agree that each person has her own natural color which looks best one them. So what Gold to be a natural color for someone may not look as good for someone else.
If I can only have one Birkin, probably black or Gold will be my choice. Because they are clasic, I can carry these colors year around, and they look good on me.
Sweetea, what's MF, is it marron fonce? If it IS marron fonce, is this a dark brown colour?