Stop in for a cup of coffee

Speaking of the behind seat panels and package trays, what do you guys recommend to use as replacement wood for those?
MDF?
Hardboard?
particle board?
or just plain old plywood?
What car? My trunk divider was basically black cardboard.
Mopar A Body 70-76 Dart Sport, Demon, Duster Trunk Divider Board - Detroit Muscle Technologies, LLC