We sent our kids to public school but we also raised all kinds of critters, had a pond, went to museums, bought science kits, had foreign language tapes, went to zoos, grew some of the herbs mentioned in books (rue, wormwood....), faithfully went to the library, explained things to our children (we both have a chem/biochem background), took our kids to see great movies about topics like global warming, and did all we could to open our children's minds. School immersed them in the important social arts that are so vital to survival. Where our schools failed/fail, we supplimented/suppliment. We had a microscope and had quite a bit of fun. The area astronomy club sets up at the local museum and we took them to see the stars. They also enjoyed the talks on astronomy.
School is only eight hours, five days a week, ten months. Your kids will share those hours with other children, learn what to do and not to do in making friends, learn independence, meet friends, make memories, encounter caring adults, and so much more. Then you have all those other hours to fill in the gaps.