My children are still in elementary school, so I don't have these high school class issues yet, but after reading this thread I'm even more convinced to follow my brother's lead with his h.s. kids: regular classes only.
It's not worth the stress in their teenage life to be loaded with APs and Honors classes when they'll still go to college and have careers with regular classes. In the big scheme of things in this life, going to college for 3 years instead of 4 is such a small reward for all the h.s. stress associated with it.
I don't believe the tons-of-AP/Honors-students learn time management and stress management: they learn how to unhealthily obsess over getting the magnificent scores to get into the magnificent colleges and they feel crap when they don't get into their first choice college. I read about it every day on College Confidential.
If your kids want to go to a top 20 - or really, even a top 50 - college, they will need to pack their schedule with honors and AP classes. Those universities don't accept students with "regular classes only." But really, it's up to each family to choose the path that is right for them.