I'm toying with building a french drain and foregoing a gutter system.
I suppose it is six of one, half dozen of another with the differences between the two systems being primarily aesthetic. The french drains are quite an old concept and only the materials to build them have changed somewhat. They can be used to channel excess water away from one area (usually around a building's foundations) to benefit another, but my own interest is in channeling the water into a cistern to use as a potable water source.
F. Drains certainly do away with the leaf and debris problem although I believe new gutter systems have almost eliminated that problem as well. I'm guessing a french drain would still present a sediment problem which could likely be fixed with some sort of settling pond or tank prior to emptying into a cistern. And I was considering whether adding charcoal to the drain's sand and gravel mix might also help with purification.
Anyhoo, I'm researching that option and wonder if anyone with experience or hydraulics expertise might have something to offer in terms of the best way to go about it.
Some google sites here:
http://images.google.com/images?hl=en&q=french%20drain&um=1&ie=UTF-8&sa=N&tab=wihttp://www.floridata.com/tracks/transplantedgardener/FrenchDrains.cfm*edited for spelling