Most of the main characters from Jump are simply cookies made from the dough of friendship, determination, and being inexplicably caught up in events that will destroy the school/town/nation/world/universe without their intervention. If you want good characters look at the bit players who serve warm-up for the villains/heros. A good example is Shikamaru from Naruto. All three main characters are various degrees of emo and "determination" (aka they won't just shut up and die) while Shikamaru is a lazy SOB who is super smart (he also doesn't have super flashy moves to spam). His fights were the only ones I actually enjoyed because it is not just spamming clones or constantly breaking out the "actual ultimate attack." Whenever crazy shit happens in his fights it doesn't seem like a contrived plot device to make sure he wins. The explanations are plausible without having to believe that the last ultimate attack failed because the villain was wearing green asbestos socks. Unfortunately it seems that writing those parts of the story is like over locking a computer: you get better results, but you can only do for so long before you fry something. Also, doing this again and again will devolve into less flashy versions of spamming ultimates.
Luffy, at the very least, dosen't have giant anti-gravity hair or, tomy knowledge, a powered-up form.
I'd say someone from FLCL, but it's too hard to say who is after what.