I tried out the Tempur Pedic in the store, but felt it was too stiff. If you are the type of person who gets comfortable and then stays in one place when you are sleeping, then it may be good for you. But the problem is that the memory foam is very stiff and feels hard when you move around. It takes about 5 seconds for the foam to adjust to your body, so for that first couple of seconds after any movement, you feel like you are laying on a hard floor covered with a blanket. Then after a few seconds, it softens up and forms the shape around your body. I am a rather restless sleeper & I move around a lot, and I felt it would just be too uncomfortable.
What I ended up getting is a Latex matress. Sealy makes a line called "Reflexion". It feels more like a regular matress, but has the back support of the memory foam. And they have several different versions, from the very soft one with the pillow top to the basic one without the pillow top. I'd definately recommend this kind of mattress.