I was contemplating this question and my answer has to be none of the above because I can’t do it. I can give you the usual:
1. Speedy B 25
2. Alma BB
2. Neverfull pm or Noe BB
But then, really, is this enough? Will you be satisfied with just those three? I just went on the website after I saw this thread and my answer is no freak’n way (for me). There are so many cute bags on there. I love the new take on the sac plat and oden. I just can’t. But I am not one of those people who can Just have one potato chip. LOL
I agree with you! But then again, that is why I am on tPF.
I have a friend who has the budget for fun handbags but is pretty tight with her money. She insisted she had her one bag and it covered what was needed. So I asked her if she's fine to just have one friend. Is that one friend enough?

I mean, you have your reliable friend, your always-up-to-party friend, your shopping friend, etc. I think I finally convinced her, but her idea of too many bags is, I think, four.
In the spirit of feeling that three is not enough, but that I'll attempt an answer anyway, my current answer for myself is:
1. SC Bag PM
2. Petite Noe
3. Neverfull GM
(This kills me because I'm actually a big bag kind of girl and the Artsy is one of my favorite bags of all time. And I have also found that the Pochette Metis is so handy.)
For others, I would probably generalize to say that I recommend:
1. SC Bag or Speedy
2. Petite Noe or Pochette Metis
3. Neverfull, whichever size suits you best