Top 5? Bwahahahah!
It's a good film, but nowhere near top 5 Material. At least, top 10.
Think about it: Casino Royale is supposed to be a Bond film that goes back to Fleming roots; The film, however, deviates amazingly far from Fleming's novel of the same name. The only one of few similarities that is even close to the novel is the title -- that is to say that, in the novel Bond drives a Bently, and in the film he drives an Aston Martin (producers tried to use the 1964 DB5 to get fans of the movies to think that it was, indeed, back to Bond roots, but Bond does not drive an Aston Martin in the Casino Royale novel); Bond also uses a Beretta in the novel, but in the film it's a Walther P99; The card game is Baccarat in the novel, but switched out for Texas Hold 'em; Another example: Bond gets tortured with a carpet beater in the Book, but this, also, is changed for an anchor rope.
Although, Casino Royale contains great moments, it is nowhere near a great Bond film -- Dr. No, From Russia With Love, Goldfinger.