I would also recommend petplan USA, website is
Petplan Pet Insurance for Dogs and Cats. We discussed this on the forum a while back and came to that conclusion. They cover herederary diseases, which no other company (to my knowledge) covers. you can also choose the amount of deductable and the amount of copayment and the rates are accordingly. I've also heard they process their claims very quick and efficiently.
I haven't had a chance to sign up with up, but will soon.