There are a few movies coming up that are based on supernatural/fantasy/science fiction books that I wanted to mention. Books from these genres especially the YA ones are now regularly becoming fodder for the Hollywood engine as more and more of them either make it to the big screen or to TV (I guess we can thank Twilight for that - if for nothing else). I generally prefer the TV series because they are longer so get to tell the story in more depth but I also think that movies often stick more to the plot of the book than TV does. This is probably for the exact same reason why I like TV more, it's length - when you have to fill so much more time you often have to add filler characters and story lines in order to keep it interesting and not overwork your main actors too much.
I really like seeing books that I have read come to life, I do prefer it with ones that are a bit older and have had time to reach a good audience I don't really see the point of releasing a book and then less than a year later the movie (except for marketing purposes to capitalize on the hype and all that). I like The Vampire Dairies because I remember it fondly from my childhood, I read and loved the original books as a teenager. After initially been not to keen on Elena being a brunette when she is blond in the book, and often described as an 'ice princess' to boot, I'm fine with the interpretation now and I like the addition of Jeremy which is a character not in the books - in the books she has a very young sister. The same goes with True Blood, after the initial pilot being really spot on and getting kudos for that - they did veer off into their own story lines making minor characters into major ones and keeping some around that died in the books - but it works and it is its own thing now. I had read the first four or so Sookie Stackhouse books that True Blood is based on quite a while before the show aired. I was initially put off by them because the covers were cartoons so it did take me a while to pick one up. I felt they were OK (a bit of fluff and fun), I was not that impressed with them so I think in the long run I have liked the TV series better. I guess in all cases there are things that you like about each of the mediums and things that you don't like.
These are some of the ones that I have noticed are coming out in 2013 and 2014 that I have read the books for so I am interested to see what the movies are like:
You can check them out on Internet Movie Database (IMDB) and Amazon:
Ender's Game - Book by Orson Scott Card
The Mortal Instruments: City of Bones - Book by Cassandra Clare
Percy Jackson: Sea of Monsters - Book by Rick Riordan
Vampire Academy: Blood Sisters - Book by Richelle Mead