That was my same reaction too. I mean, no offense, but the way he died wasn't the way I imagined L to go, because I did think that L would die (well, someone had spoiled it to me so I thought that way.
But his death wasn't the way I imagined him to go. I dislike Light a lot. God, he was so, "I'm Kira so I can do anything I want," cocky. I have to say that the anime/manga got less interesting after L died, to be honest. There was no, "mind trick," games that I could find entertaining.
And if you have yet to watch the movie, I think you'll like it better then the anime and manga.... just taking a guess.