Neal Purvis, Robert Wade, John Logan
The dynamic duo behind Bond's adventures, Neal Purvis and Robert Wade, have collaborated on six Bond scripts—The World is Not Enough (1999), Die Another Day (2002), and all four Daniel Craig romps (up to Spectre). They've basically made it their full-time jobs to pretend to be Bond.
The two were hired by Barbara Broccoli herself: she was impressed that both men could remember where they were the first time they saw a Bond film. (Um, in a movie theater?)
Barbara has also said, "It is a fine line between a Bond film and an Austin Powers film." [same source]. But Purvis and Wade have a bit of the Mike Myers in them, too: they also wrote the Bond parody Johnny English, starring Mr. Bean, a parody that wasn't nearly as beloved as the Bond movies themselves—but at least it's better than Quantum of Solace.
Playwright John Logan, who had rewritten Shakespeare for Ralph Fiennes in Coriolanus, was brought in to help with the Skyfall script, and it appears he had a lot of influence on the dialog. Logan has talked about Bond's did-he-or-didn't-he moment with Silva, a moment that suggests Bond's possible bisexuality. Logan and Craig believe that both men—Silva and Bond—were putting on a show for the sake of intimidation (source).
The three men collaborated again on Spectre, but Logan alone is rumored to be working on the script for the next Bond film (source). The other two may have to go back to pretending to be Bond for free, like the rest of us.