Sean Connery in his better Bond films is closest to the books, as Bond. Craig isn't even remotely like the Bond in the books, but I suppose the films are reacting to other franchises and even as a franchise themselves, the Bond films have created an alternative-Bond - one who's generally less interesting than the books, whether it's Roger Moore's creepy perv Bond, or Craig's thuggish bouncer. But Craig's films have had the benefit of better directors (except Quantum of Solace - which bares zilch relation to the excellent story it gets its name from), better supporting cast, huge budgets everywhere, and in fairness to Craig, he's adapted the role to fit a new audience. Asked if his martini should be shaken or stirred, he replies, do I look like I give a damn. More intensity, more emotional impact, but none of the cool or charm or suaveness, mixed with violence and hopeless womanizing that Connery carried off so effortlessly, and which is typical of the books.
I'll be very curious to see who replaces Craig, because regardless, he's been the most successful and riveting Bond in years. What direction will they take? It'll be a big challenge for them...