There are many ways to fight a battle. You don't have to be a powerful CLOSE RANGE fighter in order to be strong. Ussop is one of the most skilled marksman in the One Peice world (easily within the top ten) and that alone makes him an extremely powerful fighter. Just because he's a coward doesn't mean he isn't powerful. He's just been unable to find the "true courage of a man" so to speak. And even then, he's been showing progress throughout the series. Not to mention that even though he IS a coward, he's never been afraid to risk his life for his friends. He's put his life on the line just as often as anyone else.
But anyway, it's ignorant to say that Ussop is weak or is a poor fighter, because he's not. In terms of long-range ability, he can easily defeat most anyone. If he were to have a deathly serious match with someone like Sanji or Zoro, for example, Ussop could easily disable them before they could get close enough to strike. A well-aimed and powerful shot to the thumb, for example, would cause Zoro to not only loose his grip on his sword, but also make him unable to weild it properly thereafter. Ussop has the skill to pinpoint the exact location of such a weakness AND hit it with precise accuracy. He'd even calculate the angle should Zoro see it coming and try to dodge. Look at it this way; Ussop is probably as skill at marksmanship as Zoro is in swordmanship, if not even MORESO. They're two completely different kinds of strength, but it's still strength, nonetheless.
<a href=\'http://www.bleachportal.net/?id=interactive/pquiz/index\'><img src=\'http://www.bleachportal.net/interactive/pquiz/images/dawrewqwr.jpg\' border=\'0\'>
Take The quiz yourself</a>