From Wikipedia:

"Today, the 300SL with its unique doors, technological firsts, and low production numbers is considered one of the most collectible Mercedes-Benz models of all time, with prices reaching well past the US$650,000 mark. Sports Car International magazine ranked the 300SL as the number 5 sports car of all time. A pair of 300SLs for sale in 2009 are offered at $1.3M USD from the Foxwood Collection, demonstrating that the price of and demand for this classic remains strong.
The Mercedes-Benz SLR McLaren is inspired by these 1950s automobiles.
Mercedes-Benz still supplies parts for every car they built. The factory also provides some of the best restoration services along with a handful of top-knotch independent outfits such as Mercedes-Benz trained 300SL guru Rudiger Koniczek of Rudi & Company in British Columbia, Canada (Since 1971), Paul Russell & Company in Essex, MA, Scott Grundfor in California in the USA & HK Engineering in Germany."

To many, it's the ultimate Mercedes collectible.