i just had a thought while reading batman and robin #16. Joker said it himself that he'll fight crime which i think for him is the ultimate joke.  
 
So i'm just curious, how good a hero would the joker be?  

HORRIBLE

lol why's that?  
he's smart. he's got good detective skills. and he can fight as well. 

anti hero maybe...he'd certainly give red hood a run for his money in the whole murderous hero business...I think it'd be great to see him do it for awhile...he'd have to give it his own spin, make each bad guy/criminal he takes down into a "great" gag...

I can see him do it to mess with Batman. He'd be at the crime scene beating the sh*t outta the bad guy and then Batman would show up and be like "...Wtf are you doing?"

yeah, he would be quite an anti-hero. his main strength will be his unpredictability. lol 

Well there is a heroic counterpart the Jokester. And in The Batman animated series he actually became Batman because he was sick of losing and went around attacking citizens for minor crimes like being out after dark, jaywalking and littering.

The Jokester is the version of him that he is good unfortunately DC had not did a good job showing him. The only version I saw worked was when he was the red hood in the cartoon Batman the Brave and the Bold.    

shitty hero.... he would

There are possibilities. For one thing, Joker is considered insane or "super sane," anyway, the point is he doesn't think like everyone else, to the point that apparently murdering people for sport is okay. I have no idea how that works. Some have theorized that the Joker is the shadow of whoever fell into that vat of chemicals--he's every vice people want to exercise completely unchecked. If that's true, the Joker could be a sympathetic character because maybe his cruel vicious actions aren't really his fault but are the result of some kind of mysterious mental problem--this was an idea presented in older comics, and in Going Sane, the Joker personality goes away entirely after he thinks Batman is dead. Maybe the Joker actually has an alternate personality, not completely sane, but also not completely evil? If that's the case, maybe that personality could become an anti-hero. They keep changing his origin so much, though, that unless these theories ever appear in comics, they'll probably all be retconned away. The earlier versions of Joker, though, could have been cast as hero, anti-hero, or villain.

I always liked the whole theory that the joker realizes he is a comic character, and that he needs to create mayhem to interest the reader so that the comics continue existing.

therefore I would submit my belief that the joker is already a hero.

I totally wish they would make this theory cannon to the comics!