The Roger Moore-era films didn't always deliver, but Roger himself did. Looking back over his tenure, I think he did a great job with his deadpan delivery of the witty one-liners that contributed to his distinct tongue-in-cheek style. I'd be bold enough to say that this style has influenced some of my own writing - especially the dialogue.
As for the films, I've been watching a couple of them lately. I'd say that his best films are The Spy Who Loved Me and For Your Eyes Only. The overall winner depends on my mood. For Your Eyes Only is certainly darker and edgier than his usual fare, but the more down-to-earth story in a series of formulaic world domination plots makes it one of my favourite films in the franchise after From Russia with Love and Goldeneye. I highly rate The Spy Who Loved Me as well, although I must admit that it plays things safe and takes fewer risks. Nonetheless, it's a great escapist action flick that Moore does well. While we're on the subject, I also watched Octopussy again last night, and found it also holds up surprisingly well - an interesting mix of goofy scenes with some incredibly tense moments.
I guess I might leave it on a song, and I'll go with the theme from The Spy Who Loved Me. Because even though the franchise stumbles through many pitfalls, nobody does it better.