It looks like you're in a hot, dry climate. I would stay white (or very light) to reflect the sunlight and minimize heat gain to your house during the summer months.

I'm thinking just a touch up of the original colours would do a great job!

Definite improvement over the purple! Don't know what it's like elsewhere, but this colour scheme is very popular in our area. A shame really, it's getting a tad "over-used" and leans a bit to the monotonous/depressing side when there's too much of it. A few houses, fine - too many, not so good.

Are there any rules to follow regarding choosing exterior colours, ie, someone once told me that there should never be more than three colours, regarding the roof, walls and trims. Building a modern monoplane roof house on the coast. Like the idea of either Gull Grey or New Denim Blue for the metal roof. The interior pallette will be whites, inky navy, greys. Drawn towards grey for the weatherboard walls or white, prefer a black door. Although this is a modern house we are trying to inject a bit of modern farmhouse decor inside. Any help appreciated, thanks