Staying informed and educated about current homeschool information is important when talking to persistent skeptics. While I do not believe that as homeschoolers we should defend our decision to anyone but ourselves it is sometimes helpful to have factoid snipets to silence critics.
Rather than cite all the facts, reasonings, and rationale please read this article from The Old Schoolhouse Magazine about effectively dealing with pubic-school indoctrinated critics.
Personally, when someone asks me how homeschooling is "going" I reply with an honest answer of "It is going great. Some days are rough but we are all learning together. Homeschooling has become a wonderful blessing for my family. We are more relaxed than when we were in public school. No more rushing out the door in the morning or rushing home to get the kids. We are free to start our day whenever we want and do school wherever we want. God willing I won't ever have to deal with public school again." And yes, of course my kids get plenty of socialization. And guess what, they socialize with more than just their peer group everyday. Everyone from infants up to elderly people in our community and everything in between are in my kids socialization group now and I wouldn't have it any other way.