Why use 35 mm film raw stock and camera?
This is a debate that could go on forever. Both have pros and cons. 
I think it is inevitable that Digital will overtake Film, and we can already see it happening in that article that ObscureRobot posted. 

However, people will continue to use film as long as it is available simply because of its look. You can tell when something is shot on film because of its grain and general aesthetic.
Film is cinema as we know it.

I'd argue that this is probably the biggest reason. There are many others but I don't know enough about them to get into it. 

I think if a filmmaker can afford to use film, they will. 
This is probably the best argument for film: http://motion.kodak.com/motion/Products/Customer_Testimonials/index.htm

^ Very informative.