Wow! I really appreciate all the thought-provoking posts and the varied opinions. For once, it isn't even feasible for me to respond to each one.
Clearly, personal values and priorities play a pivotal role for this issue. I would also venture to say that the characteristic as well as the age of the child also make a major difference. I would not worry about puting my two DS among peers who are far more advantaged but it is a real concern for my DD (at least at a young age as oppose to college age) due to her personality and her attitude towards "stuff".
I do understand that many private school parents struggle to pay tuition and that there are some public schools with extremely high income demographics. However, we are not in one of those public schools and the private school is a high-end school with tuition close to $30,000 per child per year.
I have lived all over the country and have found the cost of living differences astounding. $120,000 in Des Moines, Iowa or Baton Rouge, Lousiana is far different from $120,000 in New York City or Washington, D.C. There is also the factor of one-income versus two-income as well as the number and ages of children. In my area even a decade ago, childcare costs for two babies and before/aftercare for one elementary student total around $700 per week. I am not talking nanny here but good quality center-based care. $100,000 around here would buy an old house in the equivalent of a "ghetto."
