I understand the Long Jump, but how the heck did Somersault and Triple beat out Spin Jump...
O_o
It's just not that prevalent in the 3D games, which seems to be where most people are coming from.
Sunshine by far did it the best, but by nature it feels rather loosely controlled and if you're doing levels in a sane way it's never really needed over somersault + hover.
If you know what you're doing with it, though, it's in between a double and triple jump and can be performed on the spot. Very, very effective in tight spaces, and you sacrifice just a little of the somersault's height for so much more momentum going into a hover (and it's a longer jump to start with). It's also still available while riding Yoshi, where it goes way further by default and can be augmented by a flutter. Seriously, I'm pretty sure you can jump further with a Yoshi spin jump than a Mario jump + hover. It's nuts, and you can go virtually anywhere with it.
Somersaulting is just easier though, and still very satisfying.