You don't reroof your house often, and you can't just repaint your roof like you can your siding, so it is important that pick the right color for your new shingles. There are many options on the market, and it can be difficult to find the right one to fit your home.
Grey or Black
Monotone colors, such as greys and blacks, will match with just about any siding and accent color. This makes this the safe choice if you are otherwise having trouble deciding what direction you want to go or are planning on repainting in the next few years. Since this roofing color is flexible, you can be reasonably sure it will fit the look of your new siding even if you haven't picked the color for the new trim yet. Theoretically, a black roof will absorb extra heat in the summer, making lighter greys the efficient choice, but the difference is not enough to make it a major decision piece.
If you are concerned about your roof being too boring, then you can pick a product that varies in tone from shingle to shingle. This will give you some interesting variation from the shingles to contrast the blander color scheme. However, if you are using these simpler colors to pair with a bright siding or trim color, it will be better to stick with a simpler set of tones.
Another neutral option is to go with browns or other earth tones. They work particularly well when your house is sided with materials like brick or stone. You want to match the undertones in the shingles with those in the walls, so you should bring a sample of your siding materials with you when you go to pick out your shingle color. In order to keep the house from looking too boring, you want to go with a different shade than the siding, but matching the shutters can create a particularly stunning style.
Natural tones also work well against a traditional, white house. They give some interest to the exterior of your home, without choosing a color that is too drastic. Oddball roofing colors can make your home harder to sell. While a non-traditional color may appeal to certain buyers, a neutral color will be acceptable to a wider range of potential buyers.
If you aren't planning on selling your home any time soon, the only person whose opinion you care about is your own. That allows you to take a bigger risk with your roofing color than would be a wise choice otherwise. If you are going to go with a riskier color, it is vital that you take the rest of the home's exterior into account. This is a choice that is only going to work well if the rest of your home is relatively mild. Too many bright colors, and the look will just be muddy.
If you want something that is only a little daring, you could pick a shingle color that is a mix of a brighter color, such as green or blue, and either earth tones or grey. This will add some interest to your roof without making it to glaringly bright. Just like any other roofing choice, bring in a sample of your home's exterior with you when you pick the roofing material. If you don't perfectly match the warm or cool undertones in both places, you won't be able to pull of that non-traditional roofing color.
Once you understand what different options mean for your home, it should be much easier to make the right choice. If you are still having trouble deciding, discuss your final options with your roof contractors. Years of experience will allow them to guide you through the final selection process.