If you think that shojo series are all flowery, romantic (comedies) and cheerful, you're quite wrong, and Vampire Knight will prove that more than anything else. Keywords for VK are drama, emotional struggles and tragic pasts. Throw in a dash of vampire, and there you have Vampire Knight in all its glory.
The story revolves around the students of the Cross Academy, which is divided into the Day Class for humans, and the Night Class for Vampires. The main characters, Zero and Yuki, both have very sad pasts; Zero had his family killed by a vampire, and Yuki's first memory was a vampire attacking her. These pasts, which are revealed fairly early in the series, make a good base for their relationship and their emotional struggles.
During the course of the story, the characters face one event/experience after another, which makes room for emotional struggles, lots of character development and, of course, some romance (hey, this is a shojo series after all), though the latter is overshadowed by the other stuff.
The artwork is both standard shojo and something else at the same time. We have the pretty bishonen boys in place, complete with all the fallen-head-over-heels girls, and there's also the standard shojo eyes; large, with pupils that are almost larger than the actual eyes. But since the series has a darker, sadder tone to it, there's no lack on that end either. The coloring is often very dark, and the occasional lighting effect helps on this aspect of the series.
The soundtrack is good, with sad pieces helping the sad mood, and overall good quality. There's nothing spectacular about the soundtrack though, and while the OP theme is very good, the ED theme isn't very cool, though it fits with the dark mood of the series. Voice acting is perfect; the moods are portrayed very well and there's an overall good quality.
One of the things I love about this series is the characters. I mean, I really love them. They're very deep, with their pasts and emotional struggles. Off course, there's superficial characters as well, but they're mostly supporting characters; the main characters are mostly deep and they have a lot of character development for such a short series. Their relationships with eachother are very deep too, and a pleasure to watch.
Overall, I enjoyed the series very much; this is a candidate for the best Spring 2008 anime. It's a bit open at the end, but I just read that there's a second season coming in October, so I'll accept that, and look forward to it.