The reason the 737 stood out is because it's descendents are still in use today while the 707 and DC8 are largely retired.
It was a small airliner with two engines in the rear. Although the Caravelle was retired in 2005, the twin rear engine layout was used by the very successful DC-9, MD-80 series, which is still flying, as are the similar Embraer ERJs. Twin rear mounted engines is also the design used by most private jets.