I believe that many vegetables have more nutrients (vitamins etc) when they are raw, although there are exceptions (tomatoes maybe?).
Okay, of course it's my favourite food, so I'm predjudiced, but I heard that the less you interfere with food, the better it is for you - so raw meat's better than cooked meat, and the fresher the meat is, the better.
Not totally sure about that though, so I'll check it out.
Long live Sashimi!