I've been doing mattress "research" in anticipation of buying a new queen set. We made a big mistake buying our current "top of the line" mattress 3 years ago. It was fine for the first 6 months where DH and I both felt like we were sleeping on clouds and our backs were pain free each morning. A few months later, our $1300 mattress had us each sleeping in a valley with a peak in the middle.
From what I've researched, we need to stay away from the pillow-top or luxury top (extra foam) mattresses because after they start to get indentations, we get back pain. They don't last and there are so many loopholes in the warranty with regards to indentation that you end up having to replace it a lot sooner than anticipated.
I went to the mall and spent a good two hours in the sleep number store trying out different beds (based on a recommendation from my chiropractor). I walked out of there knowing that a sleep number bed would be great if DH and I both had different "sleep numbers" or different mattress needs (softer vs firmer), but our mattress needs are the same (same sleep number), so paying all of that extra $$ for a sleep number when our numbers would be the same made no sense either.
I've read mattress user forums & other reviews and have come to the conclusion that a decent firm steel coil mattress with a separate foam topper is what we need. The foam built into the mattresses don't last 10 years, but if we buy one separately we can just replace that one as needed instead of replacing the entire mattress. We don't need another box spring, and the pillow top will be out this time. Now, which mattress we'll get -- we still aren't sure. We are leaning towards a Serta firm mattress.
What ever you decide on, go back home and read the user reviews on it before purchasing. I wish I had done that with our current mattress.