If your shingles are a dark brown, you can paint your shutters and front door a matching brown, or complimentary colour such as dark green or red and it will look very sharp. If the shingles are a lighter brown it would be safer to paint everything a dark brown colour however again you may also choose a lighter more khaki or olive green for them. I would suggest against painting them the same colour as the shingles as they would get lost among the beige of the walls.

In my opinion, any colour would be valid. You can use a same type of colour such as white, grey, brown, light blue or introduce a new colour to break with the colour monotony with a bright yellow, red, lavender, etc.