I think daily weighing is best if you can learn to take the daily fluctuations in stride, because it gives you more data points and a more realistic picture of what's going on with your body. If you're up on any given day, you can usually track it back to something you ate the day before. In an odd way, an overnight gain of a pound or more is actually kinda reassuring, because you know there's no way you ate enough the previous day to pick up a pound of actual fat! It's also helpful to calculate weekly averages and trends, which clearly show the overall downward direction even if there's an uptick on any given day.

I actually find weekly weigh-ins really disappointing if I'm up weight-wise, much more so than daily weigh-ins. If I lose a pound during the first part of the week, but then go eat salty chicken wings on Friday night, a Sunday weigh-in might just show me up 2 lbs. I won't even know I lost that pound for a whole week more, whereas if I weigh every day, I'll have a couple days to enjoy it before the water gain.