The less smooth or glossy the finished paint's surface, the better it will hide imperfections. But, the biggest revealer of imperfections will be a light placed close to the wall so that its light washes the wall's surface.
flat hides better but semigloss stays clean longer.
Eggshell is usually viewed as the best homeowner compromise.
Personally, I like the 'scrubbable flats'. Benjamin Moore has something called Matte which is my personal fave, but SW and other co's have analagous products.