"From Russia With Love" (for me, anyway) had the true cold-war feel to it, especially with all the intrique between the different groups and their infighting. It was more of a spy movie (serious-wise) than the others and even though it had its share of one-liners it was more of a realistic film. The others ("Goldfinger" excepted) soon became parodies of themselves.

I had seen the first four in their original releases and was only disappointed in "Thunderball" (too much underwater crap).