The hidden costs are those for manufacture. Cotton is incredibly bad water wise to grow I believe, so cotton nappies actually get a bit of a pummelling when it comes to that. However I still think that there is more water used to make a disposable nappy than a cloth one - especially when you consider how many times a cloth nappy is reused (all about life cycle). So while more water is used to make one cloth nappy, its much less over its lifecycle.
Power, water and chemicals are negligable. We have a swimming pool, and I was shocked to find out that our power, water and gas is still less than other people we know. I have a front loader and dry pail, so water for me is next to nothing as a cost for cleaning cloth. I dont use disposable wipes or breastpads (all cloth) so I also save money there.

Using cloth is certainly a money saver - regardless of whether you use flats or fitteds. Its more a matter of being able to budget up front and save the weekly costs I think. Cleaning them is a breeze, and SOOOO much better for the environment. How many people actually scrape their poo off 'sposies into the loo. All Jenna's waste goes through the sewerage system - where it should go. Not into landfill where we risk creating superbugs and infecting rubbish workers.

Anyway - enough harping. At the end of the day, people are happy doing what they do. Disposables are so much better than they used to be, but so is modern cloth. And its very addictive......