Everyone is different...are you a side, front or back sleeper? Being a side sleeper, a medium firmness mattress works the best for me.
This thread has perfect timing, because I'm about to get a new mattress to replace the 10-year old European Sleepworks I currently have.
After testing out various mattresses at several showrooms, I've actually settled on a latex/memory foam hybrid from Ikea. For $499, that's well within my price range. Add a topper and it still comes in well under a grand, because I already have the queen size Sleepworks adjustable slat system.
Some mattresses can be flipped, others merely rotated end-for-end. I've been doing lots of research on this website...the name is quite memorable. :laughing
Sleep Like The Dead