I always use a light malt. That way I can adjust the color and flavor myself. This is a good way for extract brewers to learn about grains.
Be aware that not all extracts are the same. As stated above, when you use darker extracts, you are not in control of what is going in your brew. Some companies, such as Breiss and Wyermann, have analysis sheets that tell what is in their extracts. These are good, if their methods are what you want.
Also, the color of extract is measured at a SG determined by the company. For example, Breiss measures their color at 30 points, and Wyermann at 50. So an extract with an advertised color of 4 by one company could also have an advertised color of 6 if sold by another company.
Enjoy