[Altaru]

L didn't really die because of his faults... He died because he couldn't predict that

1) The Shinigami (Rem, of course) actually cared enough about a human (Misa, of course) to kill him to protect her.
2) He couldn't convict Light considering that, for a time, Light was honestly not guilty.
3) Rem wouldn't tell him enough about the Death Note for him to know all of it's capabilities, and, as everyone should know, information is key to survival in that kind of cat-and-mouse game.
4) He didn't have any experience working with that which was truly paranormal.

In short, he didn't die because of his faults, but because he wasn't able to predict what would happen without the knowledge that he couldn't gain no matter how hard he tried.

Anyways, L was awesome, that cannot be denied, but if I had to choose my favorite between his sucessors, I would have to go with Near.