No contest. The Lord of the Rings trilogy. The most amazing feat of filmmaking of an epic story I think we will ever witness. The cast, the effects which were groundbreaking for the early 2000s,everything about it was fantastic. The only one nit pick I have ever had was the omission of Tom Bombadil. But aside from that, just simply the greatest non-musical films ever made for me.
Edit - having re-read the question, I think I misunderstood. I think it comes down to individual cases. I much prefer Dan Brown's Robert Langdon books to the films, although Tom Hanks is one of my favourite actors. I can watch the LOTR trilogy over and over again, yet I couldn't read the books over and over, yet I love them.
Similar vein, favourite musical, stage or screen. If both, which version do you prefer and why?