Death note is a masterpiece.
It's a clever and deceiving Anime which has two equally intelligent beings in a mind game for dominance. They're both geniuses and usually unchallenged by anyone else which creates an interesting story.
Light and L's motivations are at the core of the storyline and you will most likely be cheering on one or other.
It really is one of the best Anime around in my opinion and you need to experience it now!