Some of these upstanding members of the medical profession are the epitome of the Hippocratic oath, while others have found less ... traditional... methods of drawing blood.
Dr. Leonard McCoy ("Bones") (Star Trek)
Kind of the obvious place to start, right? It's kind of hard to think of something to say about McCoy that hasn't already been said. He's probably the original Awesome Space Doctor, providing not only medical expertise to the Enterprise, but also being one-third of the trifecta that is Kirk, Spock, and McCoy. If Spock is the logic and Kirk is emotion, then McCoy is morality glue that holds it all together. (Morality glue?) Originally portrayed by DeForest Kelley, he will be played by Karl Urban in this summer's film.
Dr. Pieter Cross (Doctor Mid-Nite) (DC Comics)
Dr. Cross is actually the third DC hero to don the mantle of Doctor Mid-Nite, and like his predecessors, he a) can only see in pitch darkness, and b) is a doctor. Despite the fact that the chosen spelling of midnight looks like the name of a bad motel, it's a little refreshing, really, to have a superhero who uses the title of "doctor" and has the medical degree to back it up. Cross, in addition to his vigilante activities, still puts in a full day at the office and is always willing to take time to deal with a medical emergency. On top of that, he's the superhero community's physician of choice, having done everything from emergency surgery on Hourman to removing the Brainiac virus from Oracle to removing a bullet from Lois Lane to giving Power Girl her annual checkups. (I kid you not; Pieter Cross is a lucky man.)
Dr. Janet Frasier (Stargate SG-1)
Dr. Frasier is basically amazing. She is a compassionate physician and finds herself not only dealing with Earth diseases, but alien ones as well, as she treats extraterrestrial refugees. Over the course of the show, she adopts a daughter, Cassandra, an alien orphan.
Dr. Owen Harper (Torchwood)
Owen is the medical officer for Torchwood Three. He's kind of sarcastic, kind of abrasive, and eventually also kind of wonderful. He spends his spare time getting romantically entangled with both of his female coworkers, a female aviator from 1953, and, well, pretty much whoever else he happens to run across. In the show's second season, he dies, but gets better. Sort of. In that he essentially becomes the team's resident snarky zombie boy for the rest of his run.
Dr. Simon Tam (Firefly TV series, Serenity, 2005 film)
A brilliant young doctor (graduating in the top three percent of his class at the Medical Academy), Simon became a resident trauma surgeon in a major hospital and his future looked bright. That is, until he has to bust his sister out of the Academy, where she's being experimented on, escape, and join up with a less-than-savory crew that conducts less-than-legal business. Lucky for him, their business tends to keep his medical training pretty well in demand. (Plus, he's pretty much a shoe-in to win Best Dressed among the ship's crew. He owns some nice waistcoats.)
Dr. Carson Beckett (Stargate: Atlantis)
If there were a competition for Most Awesome Doctor On This List, chances are Beckett probably wouldn't win, although he might earn a few points for sharing a last name with an existentialist playwright. At the same time, he's a pretty competent physician and has the honor of being the only Scottish doctor on this list. He also probably holds the honor of having the most awkward character death on here, but at least he's back now. As a clone. Which is also kind of awkward.
Dr. Victor Frankenstein (Frankenstein; or, The Modern Prometheus by Mary Wollstonecraft Shelley)
Maybe he's not exactly a certified physician, but you have admit that creating a living being out of a bunch of dead people is about as impressive as you can get when it comes to medical skill. Unfortunately for everyone concerned, however, Victor both fears and rejects his creation because of its ugliness. Way to be a pansy, man.
Dr. Thomas Elliot (Hush) (DC Comics)
He started out as Bruce Wayne's childhood friend, despite being kind of a nutjob of a kid, and went on to become a successful, Harvard-educated surgeon. Unfortunately, he eventually becomes the doctor of one Edward Nigma (The Riddler), which spells bad news, considering Elliot is the guy who tried to kill his parents as a kid (and half-succeeded) and now hates Bruce Wayne. Well, he and the Riddler realize they have that in common, and Dr. Elliot invents himself an alter-ego to work on the whole bringing-down-Batman plan. And thus, Hush is born.
Dr. Stephen Franklin (Babylon 5)
Dr. Franklin is the chief medical officer aboard the space station, and as Wikipedia describes him:
Dr. Franklin is a strong-willed, kind person and idealistic leader on Babylon 5; he is also a workaholic. He is not afraid to take risks to save a patient's life; this habit can occasionally get him into trouble. He has strong moral and ethical values, but he can also be self-righteous and a perfectionist at times.
And while those qualities make him kind of awesome, they also kind of make him addicted to stimulants in the show's third season. He, of course, beats the addiction and goes back to the awesome.
Dr. Miles Bennell (Invasion of the Body Snatchers, 1956 film)
The good doctor is called into town to look at the uncle of the cousin of his ex-sweetheart, who somehow seems not to be himself as of late. (This ex-sweetheart also seems to be able to call in some pretty convoluted favors.) Dr. Bennell is at first unable to find anything wrong, but a little more investigation leads him to discover the pod people, come to Earth to replace us. And, of course, snatch our bodies in the process-A fate which Bennell warns us of the last dramatic fourth-wall-breaking moments of the film. (The 2007 adaptation, The Invasion, features Daniel Craig as a doctor named Ben Driscoll. It unfortunately also features a bad movie.)
Dr. Sherman Cottle (Battlestar Galactica)
The Chief Medical Officer of Galactica, Dr. Cottle is also the only real physician-surgeon aboard. As the Battlestar Wiki describes him:
Cottle is somewhat eccentric and is considered a "bastard" among some of Galactica's crew, in addition to his penchant for being a heavy smoker, despite knowing the risks, and one not overly impressed by positions of power. He is, above all things, a healer. To him, nothing else really matters, be it rank, riches, or species.
Despite his somewhat abrasive manner, he's still well-trusted among the crew.
Dr. Samuel J. Loomis (Halloween franchise)
While its debatable whether or not the Halloween films are remotely science-fiction (although Michael Myers pretty inarguably displays some rather superhuman abilities), it's pretty safe to say that Dr. Loomis is just about the most awesome licensed psychiatrist in the business. After all, one of his main charges is more or less Unmitigated Evil. Then again, Loomis also doesn't have a great track record with keeping Michael from killing people. But he does get to say things like, "Death has come to your little town, Sheriff." And in Donald Pleasance's voice to boot.
Dr. Donald Blake (Thor, Marvel Comics)
Dr. Blake was Thor's original alter ego, having somewhat accidentally discovered the ability to transform into the god while on vacation in Scandanavia. Blake was a surgeon and while not being Thor, was actually seen practicing medicine in the comics. He is also said to have worked with Thor on multiple occasions, but what exactly that entails is a little beyond me.
The Doctor (Star Trek: Voyager)
The Doctor might be an Emergency Medical Hologram, but he's more than just a bit of hardware. In an attempt to build his own personality, he develops artistic talents and a holographic family, as well as friendships with his crewmates. He even writes a novel titled Photons Be Free.
Doctor Gogol (Mad Love, 1935 film)
Doctor Gogol is a brilliant-but, of course, completely mad-surgeon. After all, he's played by Peter Lorre, who pretty much invented brilliant-but-mad. Gogol is (madly) in love with an actress named Yvonne, and when her husband, a concert pianist named Stephen, has his hands crushed in a tragic accident, she comes to him, begging for help. He obliges by replacing Stephen's hands with those of a recently executed knife murderer. The results? Well, let's just say that Stephen and that kid from Idle Hands should get together and form some kind of support group. And Doctor Gogol? Completely mad. But also brilliant.
Dr. Cecilia Reyes (X-Men, Marvel Comics)
A Puerto Rican doctor, Cecilia has the ability to project a forcefield around her. As Wikipedia says:
Cecilia Reyes decided to become a doctor when her father was gunned down in front of her as a child, and she was unable to do anything to help him. The X-Men tried recruiting her when it was discovered that she was a mutant, but Reyes had no interest in being a superhero. However, when Operation: Zero Tolerance, a government-backed anti-mutant task force, targeted her, she was forced to join forces with the X-Man Iceman and other mutants to escape New York City and track down Bastion, Operation Zero Tolerance's leader.
Doc Benton (Supernatural, 3.15 "Time is on My Side")
When people started turning up with surgically removed organs and a dead man's fingerprints all over them, the Winchester brothers begin looking into it, as they are wont to do. Their investigation leads them to Doc Benton, a nineteenth century surgeon who discovered the secret to eternal life and now has a habit of replacing his parts whenever they wear out. Maybe it's not the best plan to win a guy friends, but it sure makes great use of his surgical skills.
Doctor Strauss, along with Professor Nemur (Flowers for Algernon by Daniel Keyes)
Although nobody really remembers the name of the doctor who tripled Charlie Gordon's IQ, you have to admit that pulling that off is no small feat. Unfortunately, the effects are-not to ruin the ending-not exactly all they're cracked up to be. Additionally, Strauss and Nemur can claim the credit for one of the most famous mice in sci-fi.
Dr. Julian Bashir (Star Trek: Deep Space Nine)
As Wikipedia tells it:
As a child, Julian Bashir fell behind in school, and was evaluated as having learning difficulties. Because of this, his parents, Richard and Amsha Bashir, had him subjected to genetic engineering. The procedure made him mentally superior to most humans, and greatly enhanced his physical abilities. However, because human genetic engineering is illegal in the United Federation of Planets, Bashir and his parents kept his procedure a secret throughout most of his adult life.
Throughout the course of the show, he gets to do such exciting things as end up in a prison camp, see the woman he loves (Jadzia Dax) marry someone else, and attempt to integrate some other genetically engineered people into Federation culture.
Dr. Henry Jekyll (Strange Case of Dr Jekyll and Mr Hyde by Robert Louis Stevenson)
Unlike his more temperamental counterpart, Dr. Jekyll is a well-liked, friendly doctor. The secret life he leads as Mr. Edward Hyde, however, puts that likeable reputation at stake, thanks to a potion Jekyll invented. Perhaps the lesson here is that you shouldn't mix your own drinks, even when you're a trained professional.