Definitely "Goldfinger" by Shirley Bassey. That's what Bond themes are all about.

I'd have to say that the seductive "Surrender" by k.d. lang from Tomorrow Never Dies comes a close second, though, but it was unfortunate that studio executives decided to replace it with Sheryl Crow's inferior "Tomorrow Never Dies". For me, however, "Surrender" will always be the true theme song of TND just as it was originally intended to be.