In a way, I think L outsmarted Light through his successors.

SO sad what happent to him.

He even knew what was going to happen to him in the end.

Even though L himself didn't really find Kira, I think he could have, if there was no supernatural stuff like Shinigami and stuff like that...

Both are actually really intelligent. But Light just lost it after some point.

I can't pick! >.< I WOULD say L, but I've read from sources that Light is supposed to be a little more intelligent than L. (In the manga: Light's intelligence: 9/10, L's intelligence: 8/10) But even though Light was able to outsmart others to the end (as he was slowly going insane), L still knew a lot, and he would've had the ability to find Kira.

of course it's light, he outsmarted L by killing him, light it's definitly the smartest

L obviously. Light had the unfair advantage of having the supernatural on his side.
L's deduction throughout the series was correct from the start. Light didn't outsmart L, the supernatural threw him off.

@ashura-zoldyck That is incorrect. In the Death Note novel "L: Change the World", it states that L wrote his OWN name down in the Death Note. He planned his death.

L had the Death Note for a short time on his own, and he wrote in it "L. Lawliet will die quietly of a heart attack twenty-three days from now." It explained that Watari saw that that was clearly in L's own handwriting.

L had planned and created his death the entire time. Light wasn't even aware of this.

Zeppie, that is exactly right. I agree with you 100%!