Flat paint will reflect the least amount of light, however, it easily gets scuffed/marked up if you have kids and is not as easy to clean as semigloss, for example. With that said, I painted my front screen wall Flat Black. Most people always use flat paint on ceilings throughout their house as well.

My side walls and ceiling are a dark blue in flat as well. But you could probably get by with an eggshell or semi gloss on the side walls.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85