Its my opninion but i think Naruto characters from strongest to less strong is as follows:
Pain: He defeated Jiraya!!
Jiraya: I think he was more powerfull than itachi (specially in sage mode as genjutsu wont work on him due to sage frogs and rest he can handle... i think

)
Itachi: Didn't fought sasuke on his full potential
Then comes Naruto and Sasuke (both seem to be equally powerful to me)
I havn't added many other characters!!! cuz cant think of them right now
Jiraya is quite powerful, definitely more poweful than Tsunade I think. At least, his power was focused more on fighting and hers more on healing.
Naruto did master Sage mode better than Jiraya, but Jiraya could fuse with the frogs and use sage mode for longer. Jiraya could also create Rasengan without clones, and had been using the technique for years. We have to assume his improved control would have made him better with it in a close fight (Imagine how much better Naruto will get with them this year!)
Naruto did beat Pain, but using the information that Jiraya and the rest of the villages gathered about him. Even with that info, it was a well-matched fight. It only tipped in Naruto's favor when Hinata got involved and set off Naruto's emotional reaction to turn into the 8-tail fox. Without that, Pain wouldn't have exhausted as much chakra and likely would have won in the end.
So in the end, I think your rankings are probably accurate, but they do leave out some other key characters, and they are also incomplete. We can't just rank based on "who would win in a fight", because different characters have different strengths and weaknesses. Naruto has more strength and power than Danzou has, but in a fight I think Danzou would win because of the ability gap in using genjutsu. We have to consider strength, power (chakra reserves), jutsus, weaknessess, stamina, etc. If we held a Tournament ("who would win in a fight") tomorrow, I think these would be nearly the results:
1) Pain
2) Killer Bee
3) Kisame
4) Jiraya
5) Itachi
6) Madara
7) Kakashi
8) Sasuke
9) Danzou
10) Naruto
11) Jugo
12) Tsunade
Other Akatsuki members, though powerful, were already killed by people in this list or lower. As for #1 and #2 above, it's a crapshoot whether Pain or Killer Bee would win if they fought each other. I suspect Pain would, but that's just a wild guess.
Also, if we ranked in terms of sheer power (ignoring the outcomes of individual battles) I think the rankings change significantly (I keep the numbers the same as above to compare):
2) Killer Bee
10) Naruto
3) Kisame
1) Pain
4) Jiraya
11) Jugo
12) Tsunade
5) Itachi
8) Sasuke
7) Kakashi
9) Danzou
6) Madara
My rankings for Madara are speculative because we haven't seen him do much fighting, only heard how Itachi described him ("shell of his former self"). Naruto has a crap-ton of power and potential, but is lacking the training and techniques to completely utilize it. In sage mode he can kill one of Pain's bodies with one punch. Killer Bee has a perfect pairing with his tailed beast, and that gives him lots of power (and we've seen him fight, he's stood his ground against Kisame 1:1, and against all of Taka). Kakashi is talented but his chakra reserves can be depleted quickly. Danzou has cool techniques but has shown he needs to conserve chakra. Tsunade isn't a fighter, but has a lot of chakra available for healing and summoning. Jugo has power, but we haven't seen the extent of it yet. Pain had enough chakra to power 6 bodies, who each were more powerful than several konoha warriors, and because of his many bodies he's extremely difficult to fight against fairly. Kisame is powerful, but it appears most of his ability is tied to his sword (and the sword did decide to help Killer Bee in the fight).
Somewhere in there I should include the Raikage and Gaara too, but we haven't seen enough of them recently to make comparisons. We also haven't seen Kabuto since he absorbed the remains of Orochimaru. I suspect he will be quite strong. I can't think of anybody who would really be added to both lists.