Choose both of them to be the godmother of your child. No ones feeligs get hurt for choosing one over the other.

I had done some research on godparents recently. In one culture (can't remember which), a boy traditionally has two godfathers and a godmother and a girl traditionally has two godmothers and a godfather. =]

which one will be the better role model, friend and support to your child? it took me alot of thought, and i chose my sister/best friend for my childrens godmother. she is everything that i want my children to grow up to be. honest, smart, hardworking, successful, caring, friendly, selfless.
i would think long and hard about it. and make sure you know the person real well. my husband chose the godfather, and he turned out to be completely different from who we thought he was. we are no longer on speaking terms with him, and we ended up getting a restraining order against him.

hope that helps you a little.