Dark tan, brown, or black are good neutral color choices because they will reflect less light from the screen. Be sure you don't select a paint with a glossy finish, instead go with a satin or flat finish. You don't want the finish of the paint to reflect light from the screen either.
Sherwin Williams Duration Paint is the best. It is very high quality and wont crack or peel our fade for 30 years. It is a very thick paint but also goes on incredible smooth and easy to use
You don't want a paint that is too shiny because when you watch your television the picture will shine off the wall and be an issue. Chose a color that is really cozy. Reds or darker colors are often the best choice for home theaters because actual theaters are often these colors.