Black doors

Use a gloss or semi-gloss. Easier to keep clean and won't look dull.

I think I'd prefer semi-gloss. High gloss is a very specific "wet" look that is extraordinarily reflective and may be too much "look" after the novelty wears off. Semi-gloss will give highly washable and wear-resistant finish and just be that touch more restrained. Be ready to use a lot of paint to get good even coverage.

the doors should be in a high gloss. The walls not so much

I think a black door is terribly chic. I'm with KW; high gloss might be a little too much

It depends on the smoothness of the doors ... unless they're perfect, high-gloss will look like crap in anything but very low light levels.

I see a red door and I want it painted black.

Satin finish glossy enough?

No. Satin is not semi-gloss. Satin is between eggshell and semi-gloss. I don't think I'd put that on an entrance door (at least not the part facing the public space--interior is fine).

As the saying goes, "Opinions are like a$$hole$, everybody's got one and they all stink."

Having said that, I agree with Primer05. That's the industry standard.