(MAJOR SPOILERS for eps 1-26 of Death Note below. If possible, I'd like to avoid spoilers for any of the other episodes, the manga, and the live action versions in the comments.)
I love L. I fucking love him. And I fucking love that he died. No, I mean it. It's awful. It's heart-breaking. But it's exactly right. Light is not smarter than L--it's the genius versus the savant--but Light has the answers and that's why he's got enough of an edge to stay ahead of L. And when I say "stay ahead," I do not mean, "make L think he's innocent." That's what's so glorious about these two--L knows Light's not innocent. But Light's edge is that he can make sure L has no proof to present to others. Fuckity fuck, when L realized that Light had not only engineered the loss and return of his memory as Kira, but created a proof of his innocence that he, L, would never be able to refute? Because he just didn't have the answers? That's when L knew he was dead. Doing the Dead Man Walking thing all through "Silence," knowing it's just a matter of time because Light's won.
And Light. God, I fucking love Light. There were times I loved L even more, particularly when Light turns into Lite TM, there, during his memory loss, but the story is always Light's. That's why L, not Light, has to die--because the story is Light's, about what he becomes, and L above all defines what Light becomes. And that's why losing L is bar none the most soul-shredding for him. Deciding to become god, setting up his Long Game and reliquishing his memories, getting the memories back to become Kira again--they're huge, but nevertheless Light's most extraordinary transformation is when he realizes he exists to be a foil for L, and there is no way he can ever win against L, because to win would be to beat him on L's terms, to fool him--and Light can't. All he can do is engineer L's death, and by that point, being L's foil is far too great a part of him for L's death to be a relief. L's death takes away half of what Light has become. Oh, Light. Oh, L. Oh, me. I can hardly bear it. But it's perfect, just perfect.
Nevertheless I am wailing loud and long because Light and L will never make little genius mpreg babies together. Of course I ship Light/L. *goes off to have a good cry*