You're going for contrast and it depends on your color scheme. The complimentary color to blue is ORANGE, but that's a very intense mix. You should probably go with white and use white trim on walls as an offset, either that or a light yellow. Stay away from blues or purples on the door.
I agree with Zr388, I'd choose white. But what is ironic is that there was a "Room wall color" topic, and he bumped the topic and now he's created a topic about a door...
i want to paint my door too! don't know what color though..
i'd say maybe something soft, kinda like orange, like what Zr388 said. it has to match the walls, so it can't be something deep.
I suggest you to go for white or black...
Blue walls suits with black and white door... Also if you want to make just change the shade then go for sky blue..