I still have it in there (love it!) and now my son loves looking at it too.
These maps have always had a following for decorators, but it appears they are getting more popular. Vintage school maps are fetching from $30.00-$400.00 on Ebay right now. The maps that are selling are from all areas and different illustrators. The vintage colors and perhaps the sentimentality of an area may help play a part in their desirability.
Look for them in thrift stores, Craiglist, and GovDeals.com (school districts sell a lot of surplus on this site).