I just started reading Dracula (Bram Stoker) a few days ago and so far it is really good. And it is very different than anything I've read before. I mean I've read books that are written in diary form but this is the first one where it is actually very good in keeping the suspense and mysteriousness in place. I really like how personalness of the diaries too. Frankenstein is one of my favourite books and it was a little similar in this aspect also (it had letters in it). I just read The Confessions of Max Tivoli (excellent book!) and that also was in a diary type format. But I'm still not completely sold on this type of style for novels though. I guess I don't like being dependent on the person writing the diary for whats going on in the story.