Just hit level 20 and it is time to buy my T3 runes. Saved up about 5000 IP for it.
I can finally jungle on some decent characters now, maybe
I will say this though, I have had a lot of fun jungling Nunu in games lately. I've never seen anyone use him either. Maybe he is just one of those ones that can't be used in high ELO games.
His ganks @ level 4 are good, his level 6 is great. He is a pretty strange character to build though - he scales really well with AP, but building him AP is kind of silly as it only helps 2 of his damaging abilities (with one of them only being able to be used once per team fight), so I've been trying strange hybrid types with Guinsoos and Hextec Gunblade. Coming in from behind and firing off an ice ball + Absolute Zero = one of their team goes down immediately - they can't flash out of it if you position yourself well (unless they flash directly into your team, which is certain death), at worst you can cancel it and get 2/3rd of the damage from it. Positioning is key for that Ultimate, but the damage is absolutely insane.
Just gotta be careful about hard CC characters, so sometimes it is preferable to hold it until you're engaged.