For me,I watched the anime first I think about six or seven episodes of it in that one day then I read the manga but only one volume and since the VK video game is only available,made and produced in Japan (like many anime video games) I've never played it.

i saw only 1 episode, then read the whole manga
i like the manga more then the anime :/

The anime was on TV, after obsessing and replaying all the episodes to the point of my family going crazy and sick of VK, I decided to read the manga which I later found I enjoyed more (being really unimpressed with the anime's ending)

Haha remembered I cried after the last episode of guilty, I was like "whatever will I do without Vampire Knight?!?" ^^

I actually read a chapter of the manga then watched the anime