A Cold War spy dispatching his adversary by flinging a knife across a room -- it's a trope in many movies. And they never seem to miss, or have the butt of the knife hit the target instead of the blade.
The more recent movie "Skyfall" quite explicitly harkens back to the Bond spy tech of decades back, including the Aston Martin with machine gun and ejection button (the latter provides a gag line in this movie.) More centrally to the plot, "Skyfall" also arms Bond with a knife he throws with deadly efficiency at a critical juncture.
Unlike the knife provided by "Q" in "From Russia with Love" (remember the tear gas dispensing briefcase?), or the blades wielded against Bond in "Octopussy," this weapon comes from happenstance in the field and does not appear to be a throwing knife, and certainly not a classic English combat weapons such as the Fairbairn-Sykes Fighting Knife (readers: pls correct me if this is wrong, it's only shown twice for a second or two each time.)
But Bond hurls it with deadly precision, burying it hilt-deep in his target.
So how realistic is this? The answer appears to be: Possible but unlikely.
Throwing knifes is hard, even when they're specifically designed for it. Check out the various youtube videos and web sites on it, such as http://www.throwingknives.info/
One of the main reasons is the knives are usually (thought not always, empathize the "no-spin throwers") thrown end-over-end, which injects a measure of luck in the process, even when the thrower accounts for distance and grip. Also, it's hard to get a deadly level of mass and velocity into a knife throw (unlike a knife thrust with the power of a person behind it). So getting the penetration needed for a killing strike is far from certain.
To be sure, a person who puts in substantial training with a blade balanced for throwing can achieve excellent results (which, part from the faked acts, is why so many of those lovely assistants survived their tours with carnival knife throwers.)
Far harder is throwing a knife new to you under life-or-death conditions.
As a result, knife throwing is not one of the primary skills learned by special operators and spies, though some trainers, such as the legendary, and controversial, Mike Echanis, included this skill in the larger category of "combat throwing." Echanis, who at point trained US Special Forces and has had a long following among actual operators and buffs, can be seen in a nearby picture of knife throwing from one of his books.
The best movie knife throwing in film has to be the duel between James Coburn and a gunslinger in "The Magnificant Seven." If you haven't seen it, get it. (it also includes some great small unit tactics and counter/insurgency themes.)
Bottom line: If you're not James Bond, bring a gun to the knife fight.