That many people and pets - I would go for professional services. You could try to hack it out with duty schedules, but I think in the end you'll be much happier with regular maid service. Good luck.

Hide in your very clean room!! ;)

re-elvaluate your priorites, only do what is most important and ask for help. Sometimes when my mom is stressed out I bring my kids to her house, she plays with them and I clean up around her house. Your mom/sister/hubby could just do this while you do whatever else you need to do. If your little sister still wont help, just tell her to either clean up or you will let your little ones (pets included) play with her ipod (or some such treasure).

I don't think you should waste your time/energy trying to clean/organize a house with all those people and pets. You will never be able to do it and will always feel frustrated.

I don't know how much of a "freak" you are but it might just feel better to have a little space that is yours. But is there any space in the house that you can claim as your own? A part of a basement or attic? Is there a storage shed or property where you could even build a little shed space for yourself? And when I say build, I don't mean professional construction necessarily. Maybe even something more "tree fort"-like.

And is your mom willing to lay down some cleaning rules with your sister? Being a certain age is not an excuse for sloppiness and 17 is not all that young.

Good luck!