We don't mind the stiffness, because it does go away if you fold the clothes or after you wear them for a bit. Nice stiff towels dry your body so much better too, IMO.
You can put some vinegar in your rinse cycle as a fabric softener. Also, try cutting down on the laundry soap. Soap buildup can cause stiff clothes (ever strip diapers and notice how soft they are afterwards?)
You mentioned in your other post that they dried in 30 minutes...that's quick! And also most likely why your clothes are stiffer. You can double hang clothes and they take longer to dry but they're softer.