I have a memory foam mattress (not just a topper), and it's the best mattress I've ever had. It's not the fancy brand name of Tempurpedic, but basically the same thing. Prior to that I had a waterbed, but with my back problems, I could never get the right adjustment on it, and it was murder on my back toward the end. Prior to that it was an innerspring mattress. I'll never have one of those again!

I had looked into a sleep number before I bought the Memory foam, but besides them being outrageously expensive, I read too many bad reviews. They don't hold at the number you set them at (something about atmospheric pressure affecting them), and they also tend to build up mold and mildew - can't remember why tho. There's many places on line where you can read reviews on them. My brother had one and didn't like it either, and went with a Tempurpedic, which he wouldn't trade for the world.

Hope this helps, and that you can find the system that is right for you.