The form he was in while fighting Aizen in the final battle, where he used the Final Getsuga Tensho.

I'd have to agree. I mean, if you really think about it, the comparison isn't between all of his forms. Most of the forms in that image compilation are far demonstrably weaker than others. You can basically nix the first 5 on the right completely, as well as his fullbring, since none of them hold a candle to his top forms. The full hollow form with horns is easily weaker than the final getsuga tensho, because in order to reach it, he basically had to have access to the combined power of that form and the full power of tensa zangetsu. That leaves 3 possibilities: the final getsuga tensho, the new bankai, and the hell form. None of them are directly comparable, because honestly, there's a lot we don't know about their restrictions, but from sheer size, magnitude, and destructive power, we can assume that the final getsuga tensho is the strongest.

i have to disagree i think the bevil from would come out on top. beacue his both faster and stonger and has more atks then the final genuga tenshu from.

Its not about the Final Getsuga Tensho... Just the fact that Ichigo was faster and more focused in that form. Hell Ichigo would be maybe more powerful in terms of rage, but that made him extremely reckless and unable to think or act for himself. If you recall, Ichigo was so powerful in his final form, that Aizen couldn't even detect his reiatsu, whereas Ulquiorra was strong enough to fight Ichigo in the Hell form and could sense his reiatsu.

got a point but its hard to contol your self when your dead

And that is relevant to this discussion, how? I'm just saying that no matter how powerful Hell Ichigo is, his final form is much more powerful in terms of control, focus and reiatsu... and that means that the final form would simply be much too calm and focused to allow the Hell form to hit him.

Honestly, even if we are discussing the final getsuga tensho, are you saying that the hell form would be able to take that attack without dying a horrible death, or dodge it? In either case, I'd have trouble believing it, since it is the single strongest and fastest attack we've seen to date.

My personal idea is that Ichigo, in his final Bankai form, wouldn't have needed to use it against Hell Ichigo, because he was much more calm and fluid; he hardly would have needed the help of the Final Getsuga Tensho. Let me put it this way: Aizen would have easily been able to defeat Ichigo in Hell form, while in his Hogyoku transformation, whereas he couldn't even comprehend the power of Ichigo's final Bankai form. I just watched that episode (309) and Aizen is pretty clueless. Ulquiorra didn't seem that helpless against Hell Ichigo, as opposed to how overcome Aizen became by Ichigo in his final Bankai form.

same with ulquiorra he was clueless when ichigo tranfromed.

He wasn't clueless, he figured out in about ten seconds that Ichigo wasn't in control of himself and he fought him quite a while in the same form... Aizen was far more clueless about Ichigo's power in the final Bankai form, than Ulquiorra was abot Ichigo in the Hell form.

I think his hollow form when fighting ulquiorra is the strongest made him faster stronger and even had thelat zero attack now and to top of non of the other forms had instant healing or reconstruction of a body part if it was taken off so that meant limitless power

As well as mlno body knew ulquiorras threw power but only ichigo did so in his final form he was by far the strongest spada out of the rest of the others

I'm not going to try and argue the strongest but definitely the most bad ass was full hollow while in final battle with Ulquiorra

Kisuke Urahara

without a doubt