I suppose it makes sense that I would count Jiraiya and Orochimaru up at the top if we are including them. But I have no idea why everyone seems to think that Jiraiya is stronger than Oro. We've had no comparison between them so far except that Oro's sealing technique on Naruto's belly was rough. Aside from that, Sarutobi keeps saying how Oro was the genius that comes along every couple of decades. He never said anything about Jiraiya being any good.
I don't know anything about Itachi, because I just watch the anime, but are we sure he's a jounin? All we know is that he killed most of his family and has a Konoha headband.
For the ones who we absolutely know are jounin, I would guess Kakashi, Gai, and Anko. Kakashi is Konoha's #1 technique specialist. Gai is beating Kakashi in their sparring matches. And Orochimaru said that Anko is a special jounin. I'm guessing that's a good thing.
Then again, Ebisu is a "special jounin" and I'm not too impressed with him.