I haven't a whole lot to add beyond some of the preceding great posts. But I will say that there's socialization, and there's socialization.
My kids definitely saw more children when they were in public school. And yeah, they learned a lot of things from the experience, at least superficially (and admittedly there are some instances in which I'm glad the exposure was only superficial). OTOH, we've honestly run into far more cultural and socioeconomic diversity homeschooling than we would in Suburban Heights Middle School. They've had far more opportunity to interact with people who are not age-mates. And they've been able to make real-world connections to real-world people who use the things they're studying on a regular basis: learning not just about art or math, but also about artists and accountants.
In the interest of fairness, I'll say that this is how it's worked out for us. Homeschooling in a different part of the country, where there are far better schools and more obstacles to homeschooling, might be a whole 'nother ball of wax. We're in a very homeschool-friendly part of the country, and there are a lot of us here. So our options are different than they might be in, say, rural North Dakota.
