@sabret00the:
i'll counter with: outside of fighting what has Zoro done for the crew?
Outside of fighting, in this arc alone, he blew a hole through the aqua laguna, and cut the sea train in half. All acts that could have only been performed by Zoro alone. If they had not been performed, then the SH's would have met their demise then and there. Also I'm sure Usopp has done some heroic things as well (I just can't think of any off the top of my head atm), and he does indeed contribute to the team. And also, I see where you're going with this. But that's not the point really. The point is that Usopp, despite some of the things he may have done for the Straw hats, still feels useless. From all the times he's been saved, from all the times he's felt like a coward, from all the times he's ran away, these feelings of uselessness have simply piled themselves on too thick. It's simply human really. And isn't that why many of us dig Usopp's character, for his humanity?
And the only way I see Usopp rectifying this feeling of useless is to do something grand in the end. Something that he feels no one else could have done, that only he could have done (and no fighting Jyabura would not have done this for Usopp, because Luffy, Sanji, Zoro and maybe even Robin could have done this as well, and probably with less effort even). He needs to feel important to the team, that he's needed, and that he's actually helping. Any less just wouldn't be human. I just can't see this happening any other way.
And really, what other solutions do you offer to this dilemna. That they all sit around a camp fire reminiscing about old times and singing koombaya or something?