Best time of the day to weigh-in?

Is there a specific time of day that is a better 'real' gage of your actual weight? I've heard mornings or evenings and then I've also heard you retain water over night. Is there one good time when it is more accurate?
I'm going to be weighing in at the same time every day, but I don't want to be getting excited over retained water from the night before or anything.
Also, how often do any of you weigh-in? I like to see my results, but every day is a little too emotional for me. What times work for anyone else?