These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The James Bond theme. In an interesting choice, the familiar theme music isn't played very much in the movie... until the very last scene, when James shoots Mr. White in the leg as revenge for Vesper. So the cue to the Bond theme is not only satisfying after such a long wait, but emphasizes Bond's badass attitude. It also firmly cemented both this particular 007 and, by extension, Daniel Craig, into the role.
It also pointed out an in-story Growing the Beard, with Bond finally being ready for the rigors of his job.
Ensemble Darkhorse: Mr. White, full stop. In this film and Quantum, the character has more Crowning Moments Of Awesome in his limited screen time than the two villains of both films combined. Also, Mathis qualifies with the role as aide and confidante to Craig's Bond in this film.
Foe Yay - What else can you say about a naked torture scene that starts off with the Big Bad eyeing up Bond and saying "you've taken good care of your body"? (Well, maybe ouch...).
Harsher in Hindsight: After the embassy shoot-out, M is so angry at Bond she tells him that she's seriously considering giving him up to the authorities. After Skyfall, you'll see that's no idle threat.
Older Than They Think: The idea of Bond being a humorless government-paid assassin who doesn't use gadgets and fights realistic terrorists instead of flamboyant super-criminals. Seen for the first time, this can come off as a deconstruction of the Bond mythos, but it's actually how the character was originally portrayed in Fleming's novels. Casino Royale is probably one of the most accurate adaptations of the original novels to hit the big screen.
It's also pretty much how the screen Bond was originally portrayed, in Dr. No and From Russia With Love, the first two movies of the series. In fact, the series is a whole is more cyclical on this count than anything else; it goes from grittily realistic spy thriller to progressively more over the top gadgets and villains and plots, then back to gritty realism again.
Tainted by the Preview - The second Daniel Craig, a blond, was cast to a play a character that (per Fleming's description) had been black-haired for the entire franchise, all hell broke loose. A website entitled "Daniel Craig Is Not Bond" even managed to get foreign press for all the fan ranting. Also, Moneypenny and Q weren't in the movie. Then the first trailer hit. Then the movie came out. Nobody even remembers the furor anymore. Hell, Roger Moore had brown hair anyway...
The theme song becomes this on repeated viewings: It's Bond warning his future love interests about how little they'll mean to him, as he'll never be over Vesper.
Either that or M telling Bond to harden up and get the job done, if Skyfall is anything to go by.
What an Idiot: Mendel at the end. Bond is calling him and demanding to know where the money is going and who authorized it and he just keeps smiling away without any hint that he's noticed there's anything wrong. Usually you'd think something like that would be an automatic alarm that you need to stop the transaction ASAP.
The 1954 TV film contains examples of:
It's Short, so It Sucks : It's just 54 minutes (then, again, you can see above that the other two adaptations are overly long...).