This is right up there with From Russia With Love as being one of the quintessential Bond films. I think this one might also be the most well known too, but don't quote me on that.
This one certainly has some of the most memorable quotes and moments for sure, namely the chief Bond girl's name (the deliciously unsubtle entendre of Pussy Galore), the infamous torture/intimidation scene (laser near the crotch), and the sequence with the woman in gold. It also marked a shift into the kitschy and campy realms, mostly with the gadgets and humor, but thankfully these didn't reach the heights of silliness until far later on in the series.
Bond is tasked with the fairly straightforward mission of stopping a notorious gold smuggler from robbing Fort Knox. Of course, despite how simple this sounds/seems, the quest to getting the job done is loaded with many challenges, perils, and great characters. Not only did this film really help set the tone for the rest of the series, but it also had a major hand in shaping the look, feel, and tone for many other action and adventure films of the 1960s and 70s.
Hands down required viewing for all fans of Bond, spy films, and action/adventure movies in general.