honestly, before i sleep i floss and brush always.
i dont always brush in the morning, leaves me with dog pooh for breath, cant seem to get in the habit of being as anal about it as i am night times.
either way brushing ur teeth 3x a day is important imo, really really important. but you may as well not brush at all if you're not flossing, flossing is muuuch more important. i hate bad aching teeth, they make me cry like a punk ass little bitch.