Alistar is currently very strong, and plays a support role through the jungle, normally you gank at lvl 2 and then whenever you need to, building gp10 and getting an early oracles since he NEEDS ganks to be successful. This gives great map control as Ali is fast and one who communicates with his team, is very scary.
LeeSin is really ridiculously good early to mid, but you need to snowball otherwise his poor scaling will screw you over. I like to take whichever red is closer to top lane and then gank on lvl 2. He has great damage in his Q and a strong slow in his E. Gives good dragon control with a Lantern build and easily snowballs out of control. Also has great mobility/utility for steals on objectives. His W is also great sustain.
As mentioned, Skarner is a great choice, ganking is tougher pre-six, but with practice and some number crunching on speeds, and damages you can be snowballing harder than anybody. Many people think Skarner is only there for ulti, but he gives a near constant slow, and with a triforce, or a wits end can do really good damage.
Shyvana is something I'm currently loving, her speed is ridiculous and she excels at counterganking and objective control. If you want to force a gank, it HAS to be at lvl 2, she does huge damage with red, W, and auto/Q reset. Otherwise you have to wait for people to be overextended or have lanes with lots of CC. Otherwise her clear speed and movement makes it hell for slower opposing junglers. Essentially, control objectives, and farm up for teamfights, because your AoE on W in dragon form hurts, and AoE Armor shred on E is very good utility. I recommend playing her to really learn the finer points of jungling, such as timers, and other jungler's paths. She is also hard to snowball with because she cannot MAKE someone die.
Riven is overlooked as a jungler often, but in my book can be very strong. Good gap closer to ensure damage without boots early, and good damage. Her level 2 gank is terrifying. She however needs to have successful ganks as her objective control is sub par, she also gets around map rather quickly with Q and E spam.
Nunu is a very good pickup due to the fact that he is VERY versatile, playing him AP, Support, or Tanky DPS are all strong options. His Q and W make ganks very hard to escape from without flashing, and his W scales great into late game regardless of how he builds. If your looking for a non-melee, AP Nunu is the closest thing I can give you, because of sustain from Q Nunu can do this build things like Doran's Rings and not worry about sustain. He can gank whenever and is very strong in counter jungling due to mobility,slow, and basically having two Smites.Only problem is for full damage output he needs to land a good ult, which is unrealistic with Nunu.
Nautilus was flavor of the month about a month ago, and now has somewhat fallen out of the "picked every game" category. He is still VERY strong. His W allows him to maintain health on his first clear, and do some massive DPS when ganking. Has amazing CC so he transitions well into mid and late game, his buff control is not as strong as other junglers but his ability to go balls deep makes up for that. Only downside, his counter jungling isnt as foolproof as others, and he has very week lvl 2 gank. Which generally means he needs to clear both buffs before ganking, allowing lanes to feel safer and possibly for the other jungler to have a round of ganking first.
Maokai is really strong in European Meta right now, and honestly deserves it. Maokai is so super duper omfg scary. He can gank at lvl 2, but unlike most support junglers, doesnt suffer in clear speed, or sustain if thats his choice. His ganks are almost always a guaranteed flash or kill. He has awesome utility with his ulti preventing AoE damage, and his saplings are awesome free wards. He is slightly blue dependent before he gets a Frozen heart, but with some practice and mana management shouldnt be a problem.
Nocturne is a very good jungler to start with since he has such high sustain, clear speed, and can bypass just about any wards that normally prevent ganks. While his ganks with ultimate are very strong due to their range, he also has strong pre-six ganks with his Q giving him speed, and E fearing opponents. The only thing I struggle with is working out a fine balance between being tanky, and still doing lots of damage, this is for sure only because I dont play him much, and with a little practice I'm sure you can overcome that problem really easily.
And if you actually want a ranged jungler, you can do Jayce, or karthus, but I dont know enough about either to confidently talk about them.