I did some research and they say the 5lb memory foam is what you want, and at least 8 inches of it.

I found this...

http://www.mybobs.com/Power_Bob

I am thinking about getting it. That is if I get enough responses from folks telling me they dont sleep hot. This one adjusts so I can raise my legs, or head and watch TV instead of propping with pillows.

What do you think?