Knock on wood, with the combo of Vectra 3D and the nematodes, we've not had a flea or tick issue since bringing Mila home. That said, if we ever did have a problem in the home, DE would be the way I'd go too. Glad to hear a first-hand NNer experience with it!Fleas bad here too, especially with my cat. I have had success with diamotaceous earth inside my home. It's okay to use around my kids and dries up fleas once they come in contact with it. The hard part for me is keeping it in the carpet long enough for it to be effective...it kills me not to vacuum for a week or more.
http://wolfcreekranch1.tripod.com/no_flea.html