I tried out the memory foam bed last night - you've seen the infomercials - these are the beds created with Nasa technology. They're supposed to repsond to body heat and provide better, more even support.
I liked the feeling of sinking into it, and I did sleep for 10 hours, but I'm still not sold, particularly considering the astronomical price tag. My favourite bed ever was the heavenly bed in a Peach Tree hotel in Atlanta. Now that was a comfortable bed.