Memory foam, the visco-elastic material that temporarily keeps whatever form you press into it, is mostly associated with memory foam mattresses. The most famous memory foam mattress brand is Tempur-Pedic, the very company that helped NASA to develop the material. It is one of the more premium brands, but there are at least two other quality brands worth noting.
Sensus
Sensus memory foam generally has a density of 5 pounds per cubic foot. This makes for a high-density mattress or mattress pad. It will last you at least 10 years, softening a little over time. It has an ILD (Indentation Load Deflection) of 14, which means it is a soft sort of foam. Sensus carries memory foam mattresses almost as good as Tempur-Pedic, at lower prices.
Serta
Serta is a large bedding company, formed in 1931. They decided to start offering memory foam mattresses and mattress pads in the 1990s, and their product quality is high, but their customer service is not very knowledgeable. If you buy a Serta memory foam mattress, go to a dealer or small retailer of their products, rather than the manufacturer.
Tempur-Pedic
Tempur-Pedic is the industry leader in memory foam. They offer three mattresses, each a different thickness, with different levels of firmness. The Classic is the firmest at 8”. It has a base layer of 4.3”. Air is allowed to flow through this base layer and the top two layers, with the top layer being the softest. The Deluxe is thicker at 10”, with a two-level base layer that is doubly aerated for more airflow, thus allowing for a softer and cooler sleep. The Celebrity is over 13” thick – the softest memory foam mattress Temper-Pedic has to offer. Most other companies offer these variations in memory foam mattresses, but Tempur-Pedic was the first.