How should I go about attacking my flea problem?

One of my dog's is severely allergic to fleas. As most of you probably know spot-on isn't enough because I need to treat the whole house. I have been contemplating a natural attack vs. chemical attack. The problem with natural eradication methods is that I am currently not living alone and the house is very very cluttered so it would be hard to move everything to place borax/DE every week. Chemical seems more convenient, but I have a lot of sensitive animals in my household - rodents, reptiles, fish.. And I mean a lot. So it's not like I can just move them all out of the house to spray. My cages are huge and my aquariums are huge. I also have cats so either way the method would have to be safe for cats. And most my floors are hardwood, except the basement. Advice?