Which one you favor for a  forum or website, a while and light color  or dark themes with black and gray and blend it with some other color.

Let me know your taste!!!!!     

Some rules of thumb:

Cultures are different across regions regarding preferred/standard background color.

In the West (and most other places I think), white/light background is often used for business websites.

Niches are different. Gaming websites often use darker skins.

for product introduction use website. for customers convincing use forums.

I always love light colors. that give good impression to eyes. because you site color will be good. the user will love to visit your website. that's i think.

Light colors are much better.

Color combination of white and gray will be good and look like professional. This is my suggestion, you can select as per your requirement.

The choice of colors for a forum/website often match with its niche. Let say for example forum about motherhood, cooking or about femininity are always in light colors of pink yellow or green whilst game forums use aggressive and dark colors.

I always love light colors. that give good impression to eyes. because you site color will be good. the user will love to visit your website. that's i think.

The main purpose of forums is to create communication media where people can connect with each other by making communication through post or reply and to fulfill this objective , selection of color should focus on good readability of the content shared by its users. Whether you select the dark color or light one, you have to select other property which contrast one with its back ground or font.