Well, my vote goes to Font Creator. And no, I don't have any shares in the company. But I would never have succeeded at creating a functional font, if I had not discovered this self-explaining, easy to use program. And the best about it is that it has a validation tool, which allows you to correct at least the most glaring flaws in your curves (in some cases, you can even have it correct them automatically).

I love Font Creator
I love Font Creator
I love Font Creator
I love Font Creator