I weigh daily in the morning, after the loo, in the nuddy. I use my Wii and my Salter scales (which tell me body fat, water, muscle, BMR and lbs). Interestingly the lbs are always exactly the same (so if they're up, I can blame the scales!) which is handy as I have in the past blamed poor losses on inaccurate scales, when actually it has nothing to do with them!
I don't think I'll ever stop weighing daily, or at least 3x a week.