I just wanted to say, that if you have a bad back, memory foam mattresses SUCK. They feel like heaven when you first lie down, but they react to core body heat during the night, and sorta sink in the middle of where you are sleeping, so that the middle of your back, which should have the most support, ends up in a big dip. you wake up with your back killing you. not that any mattress can help if you have a really bad back, but some help more than others.. a nice pillow top simmons beauty rest is good sometimes.. but the best way i have found to sleep is to go to a foam store, you know the kind that usually make beds for RVs and such. and get yourself a chunk of thick supportive but soft regular FOAM, and then put some egg carton toppers on it. my back still hurts in the morning, but i can pretty much sleep through the night, and don’t wake up in tears.