Just found this thread, and thought I would add my two cents. I have been researching/shopping around for a mattress for about a year now. The choice has been between the Tempurpeadic and the Select Comfort (The "number" bed). One of the intersting stats I saw, was the return rate on them during the 30 day in home trial. Don't know how reliable the state where, but over 50% of tempurpeadic's are returned and only 30% of Select Comfort (these number's could also be skewed based upon how easy it is to invoke the warranty).
One of the major complaints I found with the Tempurpedic's was the inability of the mattress to diffuse body heat. I have seen a lot of reviews where people complain that the bed gets to hot.
I only know one person that has used both beds, and he choose the Select Comfort over the Tempurpedic. Has used his for about 8 years, and is still very happy with it.
while I have yet to buy one, (it is one of those things I keep pushing off), when I finally break down and buy one I will probably go with the 5000 series Select Comfort, but I am completely open to suggestions, or thoughts otherwise.