I always love a red front door, and it's the perfect choice for this color scheme. This red door stands out from the rest of the house and attracts the guest's eye, making it clear where the guest should go.

This picture was not taken for the colors but to compare the new and old house numbers.

Here is a link to some basic reds from PANTONE.

Look at Fine Paints of Europe for an amazing glossy paint for doors. Scroll down the link for some red door photos.

http://www.finepaintsofeurope.com/inspirations-doors.aspx

Paint the door the same color red as your local Episcopal church. They’re always a good red.

What Anglophilia said. No way to improve on that.