how about Aizen? He seems pretty strong

Aizen is a tactical genius but we really do not know his full range of powers. His zanpakutoh manipulates perception which isn't about 'strength'...more about tactics. He is a master of manipulation and is played out as such for most of the manga and anime. He manipulated not only soul society but hueco mundo's espada and a number of other key characters.

Ichigo is unstable yet powerful.

Hitsugaya, if given time to grow, probably would be as strong as the old geezer as Kyouraku noted.

Ukitake is limited by his health. Kyouraku is limited because he is lazy and does not like fighting.

Shigekuni Yamamoto-Genryūsai is probably the strongest still. We have barely seen his shikai and he posses incredible strength. But he is old and often nearsighted.

Kisuke is my pick. He is not only a brilliant scientist but also a master tactician on the battlefield. He has shown that he possesses incredible strength but rarely uses it...rather relying on gadgets and inventions. I'd love to see his bankai to gauge just how strong he is but we probably won't see that for a while. =( Kisuke and Aizen are a lot alike when it comes to battle strategy...but their personalities are far different.

i would say that kenpachi is the strongest. Spoiler warning! when every body are battling there zanpakuto then kenpachi comes beating almost every zanpakuto samost without a strugle and he doesnt even now his zanpakutos name O.o

Hanatarō Yamada

easily xD

I'm going to out on a limb and say Yama-jii is the strongest of all the characters.  Because they never really let him get active.  He was going to fight his two longest serving captains, and they pretty much resigned themselves to automatic death a while back.  Then, when fighting that giant in the main arch that was whipping everyone, he killed it instantly.  He's so powerful, they even had to completely remove him from the Zanpakutou arc, thus far.  I'm going to say he is. 

Behind him, and probably when it is all said and done, Ichigo will end up being the most powerful of all characters.  He has to be, because he's the lead.  He has to save the day at the end of the anime. 

Then Zaraki Kenpachi, and then Byakuya Kuchiki. 

Ash Ketchum. Nuff said. *pokemon theme*

i think you all forget about Shunsui Kyouraku.I mean come on guys its not so easy to defeat the primera Espada using only shikai...Kenpachi, Byakuya, Ichigo this dudes kick ass but not compared with Shunsui.

and yeah i agree technicaly and theoreticaly Yama-jii shud be the most powerful chara.

Ichigo sucks. He can't control himself, and hes too much of a wuzz. Also he always has to get hit a 100 times before he goes bankai, and usually his Hollow takes over/kicks in.

Yama-Jii is currently the strongest one, though I'd say Kisuke would fight pretty even with him. He's awesome, smart and phunny!!

Hitsugaya has the best potential, as we've seen in the Zanpaktou arc, Hyorinmaru is one of the strongest ones. Also, hes the youngest one of the captains, and really, hes just awesome.

Zaraki aint nearly one of the strongest ones. I mean, hes too much of an ass. For him to get serious, you have to cut his arm off. He'd prolly still beat your ass, but he lost an arm, making him less cool in fights in the future.

Hey, I dont care. I'm rooting for Kon. Or Pikachu.

Yachiru, she's so strong that they can't show you how strong she is in the anime or manga

Muahahah!

Your all WRONG

Ichigo's dad is the strongest character-- period.

Hollow Ichigo no doubt in my mind

Well, ATM, to me, it seems that Yama-Jii has the Power AND the knowledge to be considered the strongest...
...
BUT...

I'm still waiting for "someone" to beat Ururu, and, until then, She will be the strongest of them all ^____________^