Agreed. Schwalbe Big Apple tires are very "cushy" while having the ability to take high pressure and also great puncture resistance too.

The other option if you don't want to replace the (new) tires that are already on there, you could opt for a suspension seatpost, or (for a little more money) you could get a Pantour suspension hub. (I'm not sure how much the brakes are affected by the suspension hub though?)

.... moreinfo here: http://www.pantourhub.com/products.html