We homeschooled our daughter -- she earned two Associates degrees (AA psychology, AS Criminal Justice) before her 16th birthday. She's at the top-rated private technological university in the SE right now.
Laws are state-specific, but you can find a lot of info from www.fpea.com (Florida).
We used many different curricula, depending upon the subjects and her interest -- including making up our own "unit studies." I think if we were starting over, we might look into Sonlight (kinda "Charlotte Mason" style)
Stay away from Saxon math unless you want your children to despise math and learn by rote memorization. When they get up to algebra (which can be really fast if you start out by using algebraic method to teach arithmetic), look into VideoText Algebra. It is expensive, but you can resell it for what you paid. (BTW, I use it for teaching developmental math at college)
You're just starting out, but when you are ready, look into Dr. Jay Weil's science courses. Rosetta Stone offers some of the best foreign language classes, and you can start at any age.
I disagree with your assessment of Saxon. I used it from 4th grade until the Advanced Mathematics textbook, and it prepared me to take community college classes - I started Calculus when I was 15 there. My sibs also used it or are using it and it works well for everyone I know who's used it.