Amumu is insanely good right now, but is becoming a common ban target (rightly so).

I think Jarvan IV jungle is worthy of consideration, he's fun and seems quite effective based on having jungled him some myself (recent acquisition for me).

Diana is back to being quite viable, and she is a good ganker with excellent clear speed and does fine on health too.

Riven is actually decent in the jungle too, she clears ok and has pretty decent ganks (great damage, so-so CC)

Nunu isn't seen jungling often, but he's honestly pretty good at it, and can invade like crazy too.

Cho'Gath is an excellent jungle tank, and is unlikely to solicit a ban too unlike Amumu (or even Alistar).

Alistar has some pretty amazing ganks, but he's a fairly common ban target, although I think he's becoming a less common ban.

we need a new jungle, plz. plz plz plz

The do you even nunu was about the flashbuster thing. I used to main him until a few days ago when they nerfed him hard. Reading that i have to say i disagree with a few things. First of all, his clearing isn't too great. Second of all his ganks are certainly not awful, in fact i think their above average. His slow is a good on and is ultimate is devastating. Not to mention free mobility boots and if timed right you can buff the champ in the lane your ganking. It really pisses me off when people yell at my for playing Nunu and not supporting.