Well, I'm biased, since I haven't much use for zooms! Though I do have a couple of them, almost accidentally... I tend to use them like a prime; I decide what focal length is suitable for what I anticipate shooting, set the zoom to that focal length, and then leave it there. I do not let the zoom do my walking for me!
Anyway, zooms are heavy and slow and large and expensive and have a lot of elements that may be misaligned and have reflective surfaces to cut contrast. Besides, some groups of elements move back and forth in strange patterns that make one wonder about manufacturing tolerances. All-in-all, I'm totally amazed at how well they actually work! These days, at least; zooms of the distant past can be pretty awful.
So the question is: Is the variable focal length feature so attractive to you as to overcome all the drawbacks?
Image quality? Me, I'd go for the prime, carefully chosen focal length and speed to suit what I will do most. Maybe a second prime later to cover other needs. Speed is useful not only for dim light, but to limit depth-of-field to isolate your subject or give greater sense of depth to the image. The prime is more likely to have pleasant bokeh than the zoom.
To choose your focal length, consider how far away from the people you will be, and how much of their surroundings you want to capture too. A "conversational" distance tends to give a natural sort of perspective... consider how far you are from people during a conversation. Of course it varies, and so can your photo distance for the same feeling. In some conversations you're concentrating on eyes and lips, while in others you're considering more body language and gestures or even surrounding stuff.
