You definitely have spared your family a difficult task, John. I have a similar box and went through it a few weeks ago. It's difficult chucking out sentimental items from childhood.
I like the yardstick you use - only keeping things that will be meaningful or useful to someone else.
Concert tickets are worth looking up though. I recently mentioned to my father in law that I attended the 1985 Live Aid concert. He said those tickets are selling for over $1,000 each crazy. I'm glad I didn't throw mine away!