Do you have black anywhere else in the house? I am a huge fan of black, but it has to be carried throughout to look just right. I also think (IMO) it needs to be thick trim to be black.

EEk... Can you share more pics?

This is to the left of the closet door by the front entrance

White.

Depends what you want to be as your focus?¿ White really stands out and surprising, I think black wouldn't stand out as much with your floor color and your darker furniture but make sure there's enough black in other areas to balance it...you can even use ironwork accents.

White, like all your other trim

White because the black will get lost in the dark brown and floor color!

White...because it matches your door trim. If you go black, you have to change all trim (that is attached to the space) to black...and that would look very, very odd.