IMO Lee Sin. Good through the whole game, decent cc, 2 movement skills, even reveals stealthed units, can sheild ally and has a high damage high utility ulti on a champ who doesn't use mana. Just a great jungler choice...you know, if you can land the Q.
I was here before the poll was even up, FYI!
But out of your list? Skarner! Great utility, great damage, amazing ganks...and hes a scorpion...I mean...A SCORPION! He BELONGS in the jungle...or the desert...or someones shoe...or a garage...but then Maokai is a tree, so my argument splits both ways there...But thats not the point. Skarner=epic jungler.